Dowling One Name Study

'Adam', Y Chromosomal

'Adam', Y Chromosomal

Male 579000 BC to 235000 BC - DECEASED

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  • Name 'Adam', Y Chromosomal 
    Born 579000 BC to 235000 BC  Northwest Afica Find all individuals with events at this location 
    Gender Male 
    Reference Number 163 
    Died DECEASED 
    Person ID I163  Dowling Haplogroups
    Last Modified 13 Oct 2019 

    Father 'Pre-Adam', Y Chomosomal,   d. DECEASED 
    Relationship natural 
    Family ID F98  Group Sheet  |  Family Chart

    Children 
    +1. A-1a-T,   d. DECEASED  [natural]
     2. A-1b,   d. DECEASED  [natural]
     3. A-0-P305,   b. South Cameroon, Africa Find all individuals with events at this location,   d. DECEASED  [natural]
    Last Modified 13 Oct 2019 
    Family ID F53  Group Sheet  |  Family Chart

  • Photos 2 Photos

  • Notes 
    • In human genetics, Y-chromosomal Adam (Y-MRCA) is the name given to the most recent common ancestor (MRCA) from whom all currently living people are descended patrilineally (tracing back only along the paternal or male lines of their family tree). A paper published in March 2013 determined that, with 95% confidence and that provided there are no systematic errors in the study's data, Y-chromosomal Adam lived between 237,000 and 581,000 years ago.[1] Earlier studies have estimated the date for Y-MRCA as between 60,000[2] and 142,000 years ago.[3]

      Y-chromosomal Adam is named after the biblical Adam. However, unlike his biblical namesake, the bearer of the chromosome co-existed with other human males and was not the only human male alive during his time.[4] None of his male contemporaries, however, produced a direct, unbroken male line to a male living today. Moreover, the title "Y-chromosomal Adam" is not permanently fixed on a single individual (see the section "Variable Adam" below for details).

      All living humans are also descended matrilineally from Mitochondrial Eve, who is thought to have lived approximately 200,000 years ago. Y-chromosomal Adam and Mitochondrial Eve need not have lived at the same time, nor at the same place.

      Origin

      Initial studies implicated East Africa and Southern Africa as the likely sources of human Y-chromosome diversity. This was because the basal lineages, Haplogroup A and Haplogroup B achieve their highest frequencies in these regions. But according to Cruciani et al. 2011, the most basal lineages have been detected in West, Northwest and Central Africa. In a sample of 2204 African Y-chromosomes, 8 chromosomes belonged to either haplogroup A1b or A1a. Haplogroup A1a was identified in two Moroccan Berbers, one Fulbe and one Tuareg from Niger. Haplogroup A1b was identified in three Bakola pygmies from Southern Cameroon and one Algerian Berber. Cruciani et al. 2011 suggest a Y-chromosomal Adam, living somewhere in Central-Northwest Africa, fits well with the data.[7]

      In November 2012, a study by Scozzari et al. reinforced "the hypothesis of an origin in the north-western quadrant of the African continent for the A1b haplogroup, and, together with recent findings of ancient Y-lineages in central-western Africa, provide new evidence regarding the geographical origin of human MSY diversity".[8]

      Variable Adam

      Different MRCAs (Most Recent Common Ancestor)
      The title "Y-chromosomal Adam" is not permanently fixed on a single individual. It follows from the definition of Y-chromosomal Adam that he had at least two sons who both have unbroken lineages that have survived to the present day. If the lineages of all but one of those sons die out, then the title of "Y-chromosomal Adam" shifts forward from the remaining son through his patrilineal descendants, until the first descendant is reached, who had at least two sons who both have living, patrilineal descendants.

      Once a lineage has died out it is irretrievably lost and this mechanism can thus only shift the title of "Y-chromosomal Adam" forward in time. Such an event could be due to the total extinction of several basal haplogroups.[5]

      In addition to the ability of the title of Y-chromosomal Adam to shift forward in time, the estimate of Y-chromosomal Adam's DNA sequence, his position in the family tree, the time when he lived, and his place of origin, are all subject to future revisions.

      The following events would change the estimate of who the individual designated Y-chromosomal Adam was:
      Further sampling of Y chromosomes could uncover previously unknown divergent lineages. If this happens, Y-chromosome lineages would converge on an individual who lived further back in time.
      The discovery of additional deep rooting mutations in known lineages could lead to a rearrangement of the family tree.
      Revision of the Y-chromosome mutation rate (see below) can change the estimate of the time when he lived.