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Thursday, May 11, 2023

History of the Supreme Court of the United States

The Judiciary Act of 1789 implemented the entire federal judicial branch, including the Supreme Court. It was also the first act by Congress to be partially invalidated by the Supreme Court.

The Supreme Court of the United States is the only court specifically established by the Constitution of the United States, implemented in 1789; under the Judiciary Act of 1789, the Court was to be composed of six members—though the number of justices has been nine for most of its history, this number is set by Congress, not the Constitution. The court convened for the first time on February 2, 1790.

The Old Royal Exchange, in New York City, where the first meeting of the Court was held in February 1790, though with no cases to hear.

The Jay, Rutledge, and Ellsworth Courts (1789–1801)

Image of two story brick building.
The Court lacked its own building until 1935; from 1791 to 1801, it met in Philadelphia's City Hall.

The first Chief Justice of the United States was John Jay; the Court's first docketed case was Van Staphorst v. Maryland (1791), and its first recorded decision was West v. Barnes (1791). Perhaps the most controversial of the Supreme Court's early decisions was Chisholm v. Georgia, in which it held that the federal judiciary could hear lawsuits against states. Soon thereafter, responding to the concerns of several states, Congress proposed the Eleventh Amendment, which granted states immunity from certain types of lawsuits in federal courts. The Amendment was ratified in 1795.

Jay was succeeded as Chief Justice by John Rutledge, and then by Oliver Ellsworth. No major cases came before the Supreme Court during this time.

The Supreme Court met in windowless chambers in the Capitol from 1819 until 1860. The room has been restored and is now known as the Old Supreme Court Chamber.

The Marshall Court (1801–1835)

For intending to establish three departments, co-ordinate and independent, that they might check and balance one another, it has given, according to this opinion, to one of them alone, the right to prescribe rules for the government of the others, and to that one too, which is unelected by, and independent of the nation.

— Thomas Jefferson, about the Marshall Court

One of the most significant events during the history of the Court was the tenure of Chief Justice John Marshall (1801 to 1835). In the landmark case Marbury v. Madison (1803), Marshall held that the Supreme Court could overturn a law passed by Congress if it violated the Constitution, legally cementing the power of judicial review. The Marshall Court also made several important decisions relating to federalism. Marshall took a broad view of the powers of the federal government—in particular, the interstate commerce clause and the Necessary and Proper Clause. For instance, in McCulloch v. Maryland (1819), the Court ruled that the interstate commerce clause and other clauses permitted Congress to create a national bank, even though the power to create a bank is not explicitly mentioned in the Constitution. Similarly, in Gibbons v. Ogden (1824), the Court found that the interstate commerce clause permitted Congress to regulate interstate navigation.

The Marshall Court also made several decisions restraining the actions of state governments. The notion that the Supreme Court could consider appeals from state courts was established in Martin v. Hunter's Lessee (1816) and Cohens v. Virginia (1821). In several decisions, the Marshall Court confirmed the supremacy of federal laws over state laws. For example, in McCulloch, the Court held that a state could not tax an agency of the federal government. At the same time, however, the Marshall Court held in the landmark case Barron v. Baltimore (1833) that the Bill of Rights restricted the federal government alone, and did not apply to the states. Nonetheless, the Supreme Court would in later years hold that the Fourteenth Amendment had the effect of applying most provisions of the Bill of Rights to the states.

Marshall's forceful personality allowed him to steer his fellow Justices; only once did he find himself on the losing side in a constitutional case. In that case (Ogden v. Saunders in 1827), Marshall set forth his general principles of constitutional interpretation:

To say that the intention of the instrument must prevail; that this intention must be collected from its words; that its words are to be understood in that sense in which they are generally used by those for whom the instrument was intended; that its provisions are neither to be restricted into insignificance, nor extended to objects not comprehended in them, nor contemplated by its framers; -- is to repeat what has been already said more at large, and all that can be necessary.

Marshall was in the dissenting minority only eight times throughout his tenure at the Court, partly because of his influence over the associate justices. As Oliver Wolcott observed when both he and Marshall served in the Adams administration, Marshall had the knack of "putting his own ideas into the minds of others, unconsciously to them". However, he regularly curbed his own viewpoints, preferring to arrive at decisions by consensus. He adjusted his role to accommodate other members of the court as they developed.

Marshall had charm, humor, a quick intelligence, and the ability to bring men together. His sincerity and presence commanded attention. His opinions were workmanlike but not especially eloquent or subtle. His influence on learned men of the law came from the charismatic force of his personality, and his ability to seize upon the key elements of a case and make highly persuasive arguments. Together with his vision of the future greatness of the nation, these qualities are apparent in his historic decisions and gave him the sobriquet, The Great Chief Justice.

Marshall ran a congenial court; there was seldom any bickering. The Court met in Washington only two months a year, from the first Monday in February through the second or third week in March. Six months of the year the justices were doing circuit duty in the various states. Marshall was therefore based in Richmond, his hometown, for most of the year. When the Court was in session in Washington, the justices boarded together in the same rooming house, avoided outside socializing, and discussed each case intently among themselves. Decisions were quickly made usually in a matter of days. Marshall wrote nearly half the decisions during his 33 years in office. Lawyers appearing before the court, including the most brilliant in the United States, typically gave oral arguments and did not present written briefs. The justices did not have clerks, so they listened closely to the oral arguments, and decided among themselves what the decision should be. The court issued only one decision; the occasional dissenter did not issue a separate opinion.

While Marshall was very good at listening to the oral briefs, and convincing the other justices of his interpretation of the law, he was not widely read in the law, and seldom cited precedents. After the Court came to a decision, he would usually write it up himself. Often he asked Justice Story, a renowned legal scholar, to do the chores of locating the precedents, saying, "There, Story; that is the law of this case; now go and find the authorities."

Marshall's tenure as Chief Justice has been associated with the shift towards black robes as court dress for Supreme Court judges. However, there is some evidence that indicates that the shift towards black robes occurred earlier.

The Taney Court (1836–1864)

In 1836, Marshall was succeeded as Chief Justice by Roger B. Taney, who had a somewhat more limited view of the powers of the federal government. At a time when sectional tensions between the North and South were high, many of the Supreme Court's decisions—particularly those relating to slavery—met with controversy and contention. Most controversial was the Taney Court's decision in Dred Scott v. Sandford (1857). Dred Scott, a slave from Missouri, sued for his freedom on the grounds that his master had taken him into Illinois and the territory of Wisconsin, both of which prohibited slavery, for extended periods of time. Taney, however, ruled that members of the African race were not and could never become citizens of the United States. Consequently, he ruled that Scott therefore had no standing to file the lawsuit. Moreover, he held that the Missouri Compromise, under which Congress prohibited slavery in certain territories that formed part of the Louisiana Purchase, was unconstitutional. The controversial decision met with outrage from abolitionists, and contributed to the tensions that led to the Civil War during the next decade.

The Chase, Waite, and Fuller Courts (1864–1910)

First photograph of the U.S. Supreme Court, by Alexander Gardner, 1867.

In the midst of the Civil War, Abraham Lincoln appointed Salmon P. Chase to be Chief Justice. Chase had strong anti-slavery credentials and had previously served Lincoln as Secretary of the Treasury. His post-Civil War tenure featured several key decisions affirming the indestructibility of the Union. Chase was considered highly ambitious, even for a politician. In 1872, Chase, while serving on the Supreme Court, ran for the Presidency, but his efforts were ultimately unsuccessful. Chase continued to serve as Chief Justice until his death in 1873.

In 1869, Congress increased the size of the court to consist of a chief justice and eight associate justices.

In the aftermath of the Civil War Congress passed and the states ratified the Fourteenth Amendment, which, among other things, prevented states from abridging the "privileges and immunities of citizens," from denying due process of law, and from denying equal protection of the laws to any person. Many cases that came before the Court in the post–Civil War era involved interpretation of the Fourteenth Amendment. In the Civil Rights Cases (1883), the Court under Chief Justice Morrison Waite held that Congress could not prohibit racial discrimination by private individuals (as opposed to governments) on the grounds of the Fourteenth Amendment. Later, in Plessy v. Ferguson (1896), the Court under Chief Justice Melville Fuller determined that the equal protection clause did not prohibit racial segregation in public facilities, as long as the facilities were equal (giving rise to the infamous term "separate but equal"). The sole dissenter in that case was John Marshall Harlan.

The White and Taft courts (1910–1930)

In the early twentieth century, the Supreme Court established that the Fourteenth Amendment protected the "liberty of contract." On the grounds of the Fourteenth Amendment and other provisions of the Constitution, it controversially overturned many state and federal laws designed to protect employees. The first important decision of the era was Lochner v. New York (1905), in which the Court overturned a New York law limiting the number of hours bakers could work each week. In Adair v. United States (1908), the Court overruled a federal law which forbade "yellow dog contracts" (contracts that prohibited workers from joining unions). Adkins v. Children's Hospital (1923) involved a decision that a District of Columbia minimum wage law was unconstitutional.

In 1925, the Supreme Court made a landmark ruling in Gitlow v. New York, establishing the doctrine of incorporation, under which provisions of the Bill of Rights were deemed to restrict the states. Originally, as Chief Justice John Marshall ruled in Barron v. Baltimore (1833), the Bill of Rights restricted only the federal government; however, during the twentieth century, the Supreme Court held in a series of decisions the Fourteenth Amendment had the effect of applying some (but not all) provisions of the Bill of Rights to the states. The first such decision was Gitlow, in which the Supreme Court incorporated the protection of freedom of speech afforded by the First Amendment. Important decisions relating to incorporations were made during later decades, especially the 1960s.

The Hughes, Stone, and Vinson Courts (1930–1953)

U.S. Supreme Court, 1932.

During the 1930s, the Supreme Court contained both a solid liberal bloc and a solid conservative bloc. The four conservative Justices, known as "The Four Horsemen," were James McReynolds, George Sutherland, Willis Van Devanter and Pierce Butler. Their liberal opponents on the bench – Louis Brandeis, Benjamin Cardozo and Harlan Stone, were conversely known "The Three Musketeers", while Chief Justice Charles Evans Hughes and Justice Owen Roberts controlled the balance by serving as the swing votes. Hughes, as a progressive Republican, tended to side with the Three Musketeers, whilst Roberts was swayed to the side of the conservatives.

As a result, the Court continued to enforce a Federal laissez-faire approach, overturning many of President Franklin D. Roosevelt's New Deal programs, which were designed to combat the Great Depression, by 5–4 margins. Most notably, the National Industrial Recovery Act was overturned unanimously in Schechter Poultry Corp. v. United States (1935), and the Agricultural Adjustment Act was struck down in United States v. Butler (1936).

In response, President Roosevelt proposed the Judiciary Reorganization Bill (called the "court-packing bill" by its opponents) in 1937, which would have increased the size of the Supreme Court and permitted the appointment of an additional justice for each incumbent justice who reached the age of 70 years and 6 months and refused retirement; under Roosevelt's proposal, such appointments would continue until the Court reached a maximum size of 15 justices. Ostensibly, the proposal was made to ease the burdens of the docket on the elderly justices, but Roosevelt's actual purpose was to pack the Court with justices who would support his New Deal policies and legislation. The plan quickly drew bipartisan opposition, including from Roosevelt's own vice president John Nance Garner, and it failed in Congress.

Soon afterward, however, the ideological balance of the Supreme Court that had prevailed since Lochner began to shift. Justice Roberts, who had previously voted with the conservative bloc in invalidating New Deal legislation, began to vote on the opposite side. Roberts' decision spelled the end of the Lochner era and has been dubbed the "switch in time that saved nine." The balance of the Court shifted with the retirement of Justice Van Devanter 1937 and of Justice Sutherland the following year, while Justice Butler died in November 1939. By the end of 1941, Roosevelt had appointed seven Supreme Court justices and elevated Harlan Fiske Stone to chief justice.

The Hughes and Stone Courts overturned many convictions of African-Americans in southern courts, most notably in Powell v. Alabama (1932), and laid the groundwork for postwar school desegregation in Missouri ex rel. Gaines v. Canada (1938). In one of the last cases under Chief Justice Hughes – United States v. Classic – the Court would rule that the white primaries of eight former Confederate states could be regulated as general elections were. This was followed up three years later by the landmark Smith v. Allwright (1944) which outlawed white primaries entirely and paved the way for the first significant increases in black voter registration and voting in former Confederate states since their virtually complete disenfranchisement in the 1890s.

Between 1943 and 1946, eight of the nine sitting justices had been appointed by President Roosevelt, the sole exceptions being Owen Roberts and his replacement Harold Hitz Burton. After Stone died, Fred M. Vinson was appointed Chief Justice by Harry S. Truman.

The Warren Court (1953–1969)

In 1953, President Dwight David Eisenhower appointed Earl Warren, who was then governor of California, to the position of Chief Justice. Warren's term, which lasted until 1969, was arguably one of the most significant in the history of the Court. Under him, the Court made a long series of landmark decisions. Notable members of the liberal wing of the Court aside from Warren included Hugo Black, William O. Douglas (the longest-serving Justice in the Court's history) and William J. Brennan. The foremost conservative members of the Court were Felix Frankfurter and John Marshall Harlan II (grandson of the first Justice Harlan). The first important case of Warren's tenure was Brown v. Board of Education (1954), in which the Court unanimously declared segregation in public schools unconstitutional, effectively reversing the precedent set earlier in Plessy v. Ferguson and other cases.

The Warren Court also made several controversial decisions relating to the Bill of Rights. The doctrine of incorporation, which had first taken root in Gitlow v. New York, was applied fully to most provisions of the Bill of Rights. In Engel v. Vitale (1962), the Court declared that officially sanctioned prayer in public schools was unconstitutional under the First Amendment. Similarly, in Abington School District v. Schempp (1963), it struck down mandatory Bible readings in public schools. The Court also expanded and incorporated the rights of criminal defendants, on the basis of the Fourth, Fifth, and Sixth Amendments. In Mapp v. Ohio (1961), the Court incorporated the Fourth Amendment and ruled that illegally seized evidence could not be used in a trial. Gideon v. Wainwright (1963) established that states were required to provide attorneys to indigent defendants. Miranda v. Arizona (1966) held that the police must inform suspects of their rights (including the right to remain silent and the right to an attorney) before being interrogated. (The decision is the source of the famous Miranda warning.) Another significant and controversial decision made by the Warren Court was Griswold v. Connecticut (1965), which established that the Constitution protected the right to privacy.

The Burger Court (1969–1986)

Chief Justice Earl Warren was succeeded by Warren E. Burger, who served from 1969 to 1986. The Burger Court is best remembered for its ruling in Roe v. Wade (1973), which held that there is a constitutionally protected right to have an abortion in some circumstances. The Court also made important decisions relating to the First Amendment. In Lemon v. Kurtzman (1971), it established the "Lemon test" for determining if legislation violates the establishment clause. Similarly, it established the "Miller test" for laws banning obscenity in Miller v. California (1973).

Other rulings include Landmark Communications v. Virginia in which the court ruled for fining a newspaper for revealing the identity of a judge under investigation by state commissioner H. Warrington Sharp. The Burger Court also established a moratorium on capital punishment in Furman v. Georgia (1972), holding that states generally awarded death sentences arbitrarily and inconsistently. The moratorium, however, was lifted four years later in Gregg v. Georgia (1976). Also in United States v. Nixon (1974), the court ruled that the courts have the final voice in determining constitutional questions and that no person, not even the President of the United States, is completely above law.

The Burger Court largely affirmed the Warren Court's rulings, as the liberal bloc was still led by Justices William J. Brennan, Thurgood Marshall, and John Paul Stevens. Meanwhile, Justice William Rehnquist led the conservative bloc. Many justices during this era were considered to be moderate and did not necessarily push the law in a more conservative or liberal direction.

The Rehnquist Court (1986–2005)

U.S. Supreme Court, 1998.

Chief Justice William Rehnquist served from Burger's retirement in 1986 until his own death on September 3, 2005. The Rehnquist Court generally took a limited view of Congress's powers under the commerce clause, as exemplified by United States v. Lopez (1995). The Court made numerous controversial decisions, including Texas v. Johnson (1989), which declared that flag burning was a form of speech protected by the First Amendment; Lee v. Weisman (1992), which declared officially sanctioned, student-led school prayers unconstitutional; Stenberg v. Carhart (2000), which voided laws prohibiting late-term abortions; and Lawrence v. Texas (2003), which struck down laws prohibiting sodomy. (Some commentators see these decisions as part of the "culture wars.") Another controversial decision of the Rehnquist court in 2003 was Grutter v. Bollinger which upheld affirmative action. Perhaps the most controversial decision made by the Court came in Bush v. Gore (2000), which ended election recounts in Florida following the presidential election of 2000, allowing George W. Bush to become the forty-third U.S. President.

Rehnquist led a remarkably stable Court. For the eleven years following when Stephen Breyer took the oath in 1994, to Rehnquist's death in 2005, the composition of the Court remained unchanged – the longest such stretch in over 180 years.

Justices Ruth Bader Ginsburg and John Paul Stevens led the Court's liberal bloc during this era. Meanwhile, Justices Antonin Scalia and Clarence Thomas joined Chief Justice Rehnquist as the Court's conservative bloc. Justices Sandra Day O'Connor and Anthony Kennedy were considered "swing votes" in the middle of the court, though Kennedy would protest that "the cases swing".

The Roberts Court (2005–present)

Chief Justice John G. Roberts was confirmed by the United States Senate on September 29, 2005, and presided over the Court for the first time on October 3, 2005, the day the 2005–2006 session opened. On October 31, 2005, President George W. Bush nominated Samuel Alito to replace the retiring Justice Sandra Day O'Connor (who Roberts was originally going to replace), and was confirmed on January 31, 2006. Under Roberts the Court has drifted primarily to the right in areas like the death penalty (Kansas v. Marsh), abortion (Gonzales v. Carhart and Dobbs v. Jackson Women's Health Organization), the exclusionary rule for Fourth Amendment violations (Hudson v. Michigan), and campaign-finance regulation (Citizens United v. Federal Election Commission). On November 20, 2007, the Court agreed to hear a case, District of Columbia v. Heller, that was regarded as the first important and historically significant decision on the Second Amendment to the Constitution since 1875. On March 18, 2008, the Supreme Court heard arguments concerning the constitutionality of a District of Columbia ban on handguns. On June 26, 2008, the Supreme Court ruled that "The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home."

On August 8, 2009, Sonia Sotomayor became the first Hispanic-American to serve on the Supreme Court after being nominated by Barack Obama and confirmed by the Senate to replace the retiring Justice David Souter. On May 10, 2010, President Obama nominated Elena Kagan to replace the retiring Justice John Paul Stevens. She was confirmed on August 7, 2010. On January 31, 2017, President Donald Trump nominated Neil Gorsuch to replace the late Justice Antonin Scalia (who died on February 13, 2016), and he was confirmed on April 7, 2017. On July 9, 2018, President Trump nominated Brett Kavanaugh to replace the retiring Justice Anthony Kennedy. He was confirmed on October 6, 2018.

On March 16, 2020, the Supreme Court announced it would postpone oral arguments in response to the COVID-19 pandemic, disrupting its operation for the first time in 102 years. Six months later on September 18, Ruth Bader Ginsburg died at the age of 87, opening up a seat in the Supreme Court. President Donald Trump nominated Amy Coney Barrett as a replacement on 26 September 2020, less than two months before the 2020 general election. She was confirmed by the Senate in a 52–48 vote on October 26, 2020 eight days prior to the same election. On June 30, 2022, Stephen Breyer retired, and Ketanji Brown Jackson, who was already confirmed on April 7, 2022 by a 53–47 vote, was sworn in as his replacement.

Justice Ruth Bader Ginsburg led the liberal bloc during much of this court, while Justices Antonin Scalia and Clarence Thomas led the conservative bloc. Chief Justice Roberts and Justice Anthony Kennedy were considered to be in the "middle" of the court.

Haplogroup

From Wikipedia, the free encyclopedia

A haplotype is a group of alleles in an organism that are inherited together from a single parent,and a haplogroup (haploid from the Greek: ἁπλοῦς, haploûs, "onefold, simple" and English: group) is a group of similar haplotypes that share a common ancestor with a single-nucleotide polymorphism mutation. More specifically, a haplogroup is a combination of alleles at different chromosomal regions that are closely linked and that tend to be inherited together. As a haplogroup consists of similar haplotypes, it is usually possible to predict a haplogroup from haplotypes. Haplogroups pertain to a single line of descent. As such, membership of a haplogroup, by any individual, relies on a relatively small proportion of the genetic material possessed by that individual.

Y-DNA haplogroups map of the world

Each haplogroup originates from, and remains part of, a preceding single haplogroup (or paragroup). As such, any related group of haplogroups may be precisely modelled as a nested hierarchy, in which each set (haplogroup) is also a subset of a single broader set (as opposed, that is, to biparental models, such as human family trees).

Haplogroups are normally identified by an initial letter of the alphabet, and refinements consist of additional number and letter combinations, such as (for example) A → A1 → A1a.

In human genetics, the haplogroups most commonly studied are Y-chromosome (Y-DNA) haplogroups and mitochondrial DNA (mtDNA) haplogroups, each of which can be used to define genetic populations. Y-DNA is passed solely along the patrilineal line, from father to son, while mtDNA is passed down the matrilineal line, from mother to offspring of both sexes. Neither recombines, and thus Y-DNA and mtDNA change only by chance mutation at each generation with no intermixture between parents' genetic material.

Haplogroup formation

  Ancestral haplogroup
  Haplogroup A (Hg A)
  Haplogroup B (Hg B)
All of these molecules are part of the ancestral haplogroup, but at some point in the past a mutation occurred in the ancestral molecule, mutation A, which produced a new lineage; this is haplogroup A and is defined by mutation A. At some more recent point in the past, a new mutation, mutation B, happened in a person carrying haplogroup A; mutation B defined haplogroup B. Haplogroup B is a subgroup, or subclade of haplogroup A; both haplogroups A and B are subclades of the ancestral haplogroup.

Mitochondria are small organelles that lie in the cytoplasm of eukaryotic cells, such as those of humans. Their primary function is to provide energy to the cell. Mitochondria are thought to be reduced descendants of symbiotic bacteria that were once free living. One indication that mitochondria were once free living is that each contains a circular DNA, called mitochondrial DNA (mtDNA), whose structure is more similar to bacteria than eukaryotic organisms (see endosymbiotic theory). The overwhelming majority of a human's DNA is contained in the chromosomes in the nucleus of the cell, but mtDNA is an exception. An individual inherits their cytoplasm and the organelles contained by that cytoplasm exclusively from the maternal ovum (egg cell); sperm only pass on the chromosomal DNA, all paternal mitochondria are digested in the oocyte. When a mutation arises in a mtDNA molecule, the mutation is therefore passed in a direct female line of descent. Mutations are changes in the nitrogen bases of the DNA sequence. Single changes from the original sequence are called single nucleotide polymorphisms (SNPs).

Human Y chromosomes are male-specific sex chromosomes; nearly all humans that possess a Y chromosome will be morphologically male. Although Y chromosomes are situated in the cell nucleus and paired with X chromosomes, they only recombine with the X chromosome at the ends of the Y chromosome; the remaining 95% of the Y chromosome does not recombine. Therefore, the Y chromosome and any mutations that arise in it are passed on from father to son in a direct male line of descent. This means the Y chromosome and mtDNA share specific properties.

Other chromosomes, autosomes and X chromosomes in women, share their genetic material (called crossing over leading to recombination) during meiosis (a special type of cell division that occurs for the purposes of sexual reproduction). Effectively this means that the genetic material from these chromosomes gets mixed up in every generation, and so any new mutations are passed down randomly from parents to offspring.

The special feature that both Y chromosomes and mtDNA display is that mutations can accrue along a certain segment of both molecules and these mutations remain fixed in place on the DNA. Furthermore, the historical sequence of these mutations can also be inferred. For example, if a set of ten Y chromosomes (derived from ten different men) contains a mutation, A, but only five of these chromosomes contain a second mutation, B, then it must be the case that mutation B occurred after mutation A.

Furthermore, all ten men who carry the chromosome with mutation A are the direct male line descendants of the same man who was the first person to carry this mutation. The first man to carry mutation B was also a direct male line descendant of this man, but is also the direct male line ancestor of all men carrying mutation B. Series of mutations such as this form molecular lineages. Furthermore, each mutation defines a set of specific Y chromosomes called a haplogroup.

All men carrying mutation A form a single haplogroup, and all men carrying mutation B are part of this haplogroup, but mutation B also defines a more recent haplogroup (which is a subgroup or subclade) of its own to which men carrying only mutation A do not belong. Both mtDNA and Y chromosomes are grouped into lineages and haplogroups; these are often presented as tree-like diagrams.

Haplogroup population genetics

It is usually assumed that there is little natural selection for or against a particular haplotype mutation which has survived to the present day, so apart from mutation rates (which may vary from one marker to another) the main driver of population genetics affecting the proportions of haplotypes in a population is genetic drift—random fluctuation caused by the sampling randomness of which members of the population happen to pass their DNA on to members of the next generation of the appropriate sex.

This causes the prevalence of a particular marker in a population to continue to fluctuate, until it either hits 100%, or falls out of the population entirely. In a large population with efficient mixing the rate of genetic drift for common alleles is very low; however, in a very small interbreeding population the proportions can change much more quickly. The marked geographical variations and concentrations of particular haplotypes and groups of haplotypes therefore witness the distinctive effects of repeated population bottlenecks or founder events followed by population separations and increases.

The lineages which can be traced back from the present will not reflect the full genetic variation of the older population: genetic drift means that some of the variants will have died out. The cost of full Y-DNA and mtDNA sequence tests has limited the availability of data; however, their cost has dropped dramatically in the last decade. Haplotype coalescence times and current geographical prevalences both carry considerable error uncertainties. This is especially troublesome for coalescence times, because most population geneticists still continue (albeit decreasing a little bit) to use the "Zhivotovski method", which is heavily criticised by DNA-genealogists for its falsehood. The eusocial wasp Angiopolybia pallens presents with 8 haplogroups depending on its location. This displays the idea of genetic drift.

Human Y-chromosome DNA haplogroups

Y-chromosomal Adam is the name given by researchers to the male who is the most recent common patrilineal (male-lineage) ancestor of all living humans.

Major Y-chromosome haplogroups, and their geographical regions of occurrence (prior to the recent European colonization), include:

Groups without mutation M168

Groups with mutation M168

(mutation M168 occurred ~50,000 bp)

  • Haplogroup C (M130) (Oceania, North/Central/East Asia, North America and a minor presence in South America, Southeast Asia, South Asia, West Asia, and Europe)
  • YAP+ haplogroups
    • Haplogroup DE (M1, M145, M203)
      • Haplogroup D (CTS3946) (Tibet,Nepal,Japan, the Andaman Islands, Central Asia, and a sporadic presence in Nigeria, Syria, and Saudi Arabia)
      • Haplogroup E (M96)
        • Haplogroup E1b1a (V38) West Africa and surrounding regions; formerly known as E3a
        • Haplogroup E1b1b (M215) Associated with the spread of Afroasiatic languages; now concentrated in North Africa and the Horn of Africa, as well as parts of the Middle East, the Mediterranean, and the Balkans; formerly known as E3b

Groups with mutation M89

(mutation M89 occurred ~45,000 bp)

  • Haplogroup F (M89) Oceania, Europe, Asia, North and South America
  • Haplogroup G (M201) (present among many ethnic groups in Eurasia, usually at low frequency; most common in the Caucasus, the Iranian plateau, and Anatolia; in Europe mainly in Greece, Italy, Iberia, the Tyrol, Bohemia; rare in Northern Europe)
  • Haplogroup H (L901/M2939)
    • H1'3 (Z4221/M2826, Z13960)
      • H1 (L902/M3061)
        • H1a (M69/Page45) India, Sri Lanka, Nepal, Pakistan, Iran, Central Asia
        • H1b (B108) Found in a Burmese individual in Myanmar.
      • H3 (Z5857) India, Sri Lanka, Pakistan, Bahrain, Qatar
    • H2 (P96) Formerly known as haplogroup F3. Found with low frequency in Europe and western Asia.
  • Haplogroup IJK (L15, L16)

Groups with mutations L15 & L16

Groups with mutation M9

(mutation M9 occurred ~40,000 bp)

  • Haplogroup K
    • Haplogroup LT (L298/P326)
      • Haplogroup L (M11, M20, M22, M61, M185, M295) (South Asia, Central Asia, Southwestern Asia, the Mediterranean)
      • Haplogroup T (M70, M184/USP9Y+3178, M193, M272) (North Africa, Horn of Africa, Southwest Asia, the Mediterranean, South Asia); formerly known as Haplogroup K2
    • Haplogroup K(xLT) (rs2033003/M526)
Groups with mutation M526

Human mitochondrial DNA haplogroups

Human migrations and mitochondrial haplogroups
 

Human mtDNA haplogroups are lettered: A, B, C, CZ, D, E, F, G, H, HV, I, J, pre-JT, JT, K, L0, L1, L2, L3, L4, L5, L6, M, N, P, Q, R, R0, S, T, U, V, W, X, Y, and Z. The most up-to-date version of the mtDNA tree is maintained by Mannis van Oven on the PhyloTree website.

Phylogenetic tree of human mitochondrial DNA (mtDNA) haplogroups

  Mitochondrial Eve (L)    
L0 L1–6  
L1 L2   L3     L4 L5 L6
M N  
CZ D E G Q   O A S R   I W X Y
C Z B F R0   pre-JT   P   U
HV JT K
H V J T

Mitochondrial Eve is the name given by researchers to the woman who is the most recent common matrilineal (female-lineage) ancestor of all living humans.

Defining populations

Map of human haplotype migration, according to mitochondrial DNA, with key (coloured) indicating periods in numbered thousands of years before the present.

Haplogroups can be used to define genetic populations and are often geographically oriented. For example, the following are common divisions for mtDNA haplogroups:

The mitochondrial haplogroups are divided into three main groups, which are designated by the sequential letters L, M, N. Humanity first split within the L group between L0 and L1-6. L1-6 gave rise to other L groups, one of which, L3, split into the M and N group.

The M group comprises the first wave of human migration which is thought to have evolved outside of Africa, following an eastward route along southern coastal areas. Descendant lineages of haplogroup M are now found throughout Asia, the Americas, and Melanesia, as well as in parts of the Horn of Africa and North Africa; almost none have been found in Europe. The N haplogroup may represent another macrolineage that evolved outside of Africa, heading northward instead of eastward. Shortly after the migration, the large R group split off from the N.

Haplogroup R consists of two subgroups defined on the basis of their geographical distributions, one found in southeastern Asia and Oceania and the other containing almost all of the modern European populations. Haplogroup N(xR), i.e. mtDNA that belongs to the N group but not to its R subgroup, is typical of Australian aboriginal populations, while also being present at low frequencies among many populations of Eurasia and the Americas.

The L type consists of nearly all Africans.

The M type consists of:

M1 – Ethiopian, Somali and Indian populations. Likely due to much gene flow between the Horn of Africa and the Arabian Peninsula (Saudi Arabia, Yemen, Oman), separated only by a narrow strait between the Red Sea and the Gulf of Aden.

CZ – Many Siberians; branch C – Some Amerindian; branch Z – Many Saami, some Korean, some North Chinese, some Central Asian populations.

D – Some Amerindians, many Siberians and northern East Asians

E – Malay, Borneo, Philippines, Taiwanese aborigines, Papua New Guinea

G – Many Northeast Siberians, northern East Asians, and Central Asians

Q – Melanesian, Polynesian, New Guinean populations

The N type consists of:

A – Found in many Amerindians and some East Asians and Siberians

I – 10% frequency in Northern, Eastern Europe

S – Some Australian aborigines

W – Some Eastern Europeans, South Asians, and southern East Asians

X – Some Amerindians, Southern Siberians, Southwest Asians, and Southern Europeans

Y – Most Nivkhs and people of Nias; many Ainus, Tungusic people, and Austronesians; also found with low frequency in some other populations of Siberia, East Asia, and Central Asia

R – Large group found within the N type. Populations contained therein can be divided geographically into West Eurasia and East Eurasia. Almost all European populations and a large number of Middle-Eastern population today are contained within this branch. A smaller percentage is contained in other N type groups (See above). Below are subclades of R:

B – Some Chinese, Tibetans, Mongolians, Central Asians, Koreans, Amerindians, South Siberians, Japanese, Austronesians

F – Mainly found in southeastern Asia, especially Vietnam; 8.3% in Hvar Island in Croatia.

R0 – Found in Arabia and among Ethiopians and Somalis; branch HV (branch H; branch V) – Europe, Western Asia, North Africa;

Pre-JT – Arose in the Levant (modern Lebanon area), found in 25% frequency in Bedouin populations; branch JT (branch J; branch T) – North, Eastern Europe, Indus, Mediterranean

U – High frequency in West Eurasia, Indian sub-continent, and Algeria, found from India to the Mediterranean and to the rest of Europe; U5 in particular shows high frequency in Scandinavia and Baltic countries with the highest frequency in the Sami people.

Y-chromosome and MtDNA geographic haplogroup assignation

Here is a list of Y-chromosome and MtDNA geographic haplogroup assignation proposed by Bekada et al. 2013.

Y-chromosome

According to SNPS haplogroups which are the age of the first extinction event tend to be around 45–50 kya. Haplogroups of the second extinction event seemed to diverge 32–35 kya according to Mal'ta. The ground zero extinction event appears to be Toba during which haplogroup CDEF* appeared to diverge into C, DE and F. C and F have almost nothing in common while D and E have plenty in common. Extinction event #1 according to current estimates occurred after Toba, although older ancient DNA could push the ground zero extinction event to long before Toba, and push the first extinction event here back to Toba. Haplogroups with extinction event notes by them have a dubious origin and this is because extinction events lead to severe bottlenecks, so all notes by these groups are just guesses. Note that the SNP counting of ancient DNA can be highly variable meaning that even though all these groups diverged around the same time no one knows when.

Father Tongue hypothesis

From Wikipedia, the free encyclopedia
 
Language families and Y-DNA distributions in Africa
 
Distribution of language families
 
Distribution of Y-DNA:E1b1a(Related to Niger-Congo languages
 
Distribution of Y-DNA:E1b1b(Related to Afro-Asiatic languages
 
Distribution of Y-DNA:A(Related to Khoisan languages and part of Nilo-Saharan languages

The Father Tongue hypothesis proposes that humans tend to speak their father's language. It is based on the discovery, in 1997, of a closer correlation between language and Y-chromosomal variation than between language and mitochondrial DNA variation. The initial work was performed on African and European samples by a team of population geneticists led by Laurent Excoffier. On the basis of these and similar findings by other geneticists, the hypothesis was elaborated by historical linguist George van Driem in 2010 that the teaching by a mother of her spouse's tongue to her children is a mechanism by which language has preferentially been spread over time.

Focusing on prehistoric language shift in already settled areas, examples worldwide show that as little as 10–20% of prehistoric male immigration can (but need not) cause a language switch, indicating an elite imposition such as may have happened with the appearance of the first farmers or metalworkers in the Neolithic, Bronze and Iron Ages.

Early autosomal research

Before the discovery of mtDNA variation and Y-chromosomal variation in the 1980s and 1990s, respectively, it was not possible to distinguish male from female effects in population genetics. Instead, researchers had to rely on autosomal variation, starting with the first population genetic study using blood groups by Ludwik Hirszfeld in 1919. Later other genetic polymorphisms were used, for example polymorphisms of proteins of the blood plasma, polymorphisms of human lymphocyte antigens or polymorphisms of immunoglobulins. On this basis, correlations between languages and genetic variation occasionally were proposed, but sex-specific questions could not be addressed until the 1990s, when both mtDNA and Y-chromosomal variation in humans became available for study.

Origin of the hypothesis

The Y chromosome follows patrilineal inheritance, meaning it is only passed on among males, from father to son. Mitochondrial DNA on the other hand follows matrilineal inheritance, meaning it is only passed on from the mother to her children and from her daughters to their children. In 1997 Laurent Excoffier, his student Estella Poloni and his team reported that they had found a strong correlation between the Y-chromosomal sequence P49a,f/Taql variation and linguistics, while not being able to find such a correspondence for the mtDNA variation. Poloni et al. proposed the possible consequences of such a correlation, i.e. the Father Tongue hypothesis:

"As a consequence, the female-specific diversity of our genome would fit less well with geography and linguistics than would our male-specific component. [...] If that were to prove to be the case, then the common belief that we speak our mother's tongue should be revised in favor of the concept of a ‘father's tongue’."

Estella Poloni also presented the Father Tongue hypothesis at an international conference in Paris in April 2000.

On the basis of this population genetic work, historical linguist George van Driem elaborated the Father Tongue hypothesis in his ethnolinguistic publications and in population genetic publications which he has co-authored. At the Indo-Pacific Prehistory Association conference in Taipei in 2002 he proposed that

"a mother teaching her children their father’s tongue has been a recurrent, ubiquitous and prevalent pattern throughout linguistic history, […] some of the mechanisms of language change over time are likely to be inherent to the dynamics of this pathway of transmission. Such correlations are observed worldwide."

Discovery of Y-chromosomal markers for languages

The next development was the discovery of specific Y-chromosomal markers linked to a language. These Y-chromosomal variants do not cause language change, but happened to be carried by the historic or prehistoric male speakers spreading the language. These language-specific Y-chromosomal markers create correlations such as those observed by Poloni et al. 1997, and furthermore allow the geographic extent, the time depth and the male immigration level underlying an unrecorded (prehistoric) language change to be determined.

Examples of father tongues

Distributions of Uralic languages and Y-DNA:N
 
Distribution of Uralic languages (and Yukaghir languages)
 
Distribution of Haplogroup N (Y-DNA)
Distributions of Sino-Tibetan languages and Y-DNA:O2
Distribution of Sino-Tibetan languages
Distribution of Haplogroup O2 (Y-DNA)

There are several salient examples where the prehistoric diffusion of a language family correlates strongly with the diffusion of Y-chromosomal haplogroups.

  • The dispersal of Indo-Europeans from a proposed homeland in the Pontic–Caspian steppe according to the Kurgan hypothesis is suggested to be linked to the spread of the R haplogroup subclade, R1a1, into Europe. R1a1 may also reflect the arrival of the Indo-Aryans into northern India.
  • The Y-chromosomal lineage L could potentially reflect an earlier patrilingual dispersal of Elamo-Dravidian emanating from a region in modern day Iran. However, the Elamo-Dravidian proposal continues to be rejected by mainstream linguists.
  • Austroasiatic speakers show a high frequency of the O2a haplogroup subclade. For example, Munda speakers in north and northeast India show high frequencies of O2a, not found in their regional neighbours who speak languages other than Austroasiatic, whilst their mtDNA haplogroups seem to be those frequent in their region independent of language affinity.
  • A population genetic study of 23 Han Chinese populations has shown that the Han expansion southward during the sinification of what today is southern China was predominantly male-biased and is an uncontroversial example of the Father Tongue hypothesis.
  • It has also been suggested that Bantu and other Niger-Congo languages correlate well with Y-chromosomal haplogroups.
  • The spread of Afroasiatic languages has been linked to the expansion of E1b1b haplogroup.

Implications

The Father Tongue hypothesis has far-reaching implications for several processes in linguistics such as language change, language acquisition and sociolinguistics. The Father Tongue hypothesis also has implications for language acquisition, as the hypothesis suggests an evolutionary explanation for why females may be better in some aspects of language performance and acquisition.

The historical linguist George van Driem interpreted the correlation of Y-chromosomal haplogroups and language families as indicating that the spread of language families was often mediated by male-biased migration, whether these intrusions were martial or something less spectacular. He conjectured that the majority of language communities spoke father tongues rather than mother tongues.

The Father Tongue hypothesis has implications for linguists' understanding of language change. It must be assumed that the dynamics of language change whereby mothers pass on the language of their spouses to their offspring differ from the dynamics of language change in a monolingual community and even from the dynamics of change in a bilingual community where mothers pass on their own language to their children. As a consequence, such dynamics can introduce a discontinuity with the past. For example, it has been observed that Michif, genetically an Algonquian language (like Plains Cree), was relexified by Métis women with Métis French, the language of their husbands, and so the genetic affinity of Michif has come to be almost unidentifiable. If the process of relexification went beyond the possibility of linguistic reconstruction, the dynamics of such a process may obscure the true linguistic heritance of a community.

Exceptions

Genetics does not determine the language spoken by a human being, and the link between Y-chromosomal haplogroups and linguistic affinities is an observed correlation and not a causal link. While father tongues predominate, exceptions to father tongues exist in the world. Two very well-known exceptions are the Balti in northern Pakistan and Hungarians. The mtDNA haplogroups most frequent among Balti are the same as those of the neighbouring Tibetan communities, whereas the Y-chromosomal haplogroups most frequent in Balti males appear to have entered Baltistan from the west with the introduction of Islam. The Balti speak one of the most conservative Tibetan languages. The language of the Balti corresponds to the mtDNA and not to the Y chromosome and is in effect a salient example of a mother tongue. The other well-known exception is Hungarian. The N1c haplogroup of the Y chromosome, distinguished by Tat-C deletion, is found at a high frequency throughout Uralic language communities, but is virtually missing in Hungarian males. Therefore, while the intrusion of the Magyars into what is today Hungary is historically attested and has left clear linguistic evidence, genetically the Magyar intrusion has left no salient genetic traces. Instead, from a genetic point of view, Hungarians strongly resemble a Western Slavic language community.

 

Cooperative

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