Post by zarahan on Aug 23, 2015 23:26:33 GMT -5
A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa
Fulvio Cruciani, Beniamino Trombetta, Andrea Massaia, Giovanni Destro-Bisol, Daniele Sellitto, Rosaria Scozzari
DOI: dx.doi.org/10.1016/j.ajhg.2011.05.002
To shed light on the structure of the basal backbone of the human Y chromosome phylogeny, we sequenced about 200 kb of the male-specific region of the human Y chromosome (MSY) from each of seven Y chromosomes belonging to clades A1, A2, A3, and BT. We detected 146 biallelic variant sites through this analysis. We used these variants to construct a patrilineal tree, without taking into account any previously reported information regarding the phylogenetic relationships among the seven Y chromosomes here analyzed. There are several key changes at the basal nodes as compared with the most recent reference Y chromosome tree. A different position of the root was determined, with important implications for the origin of human Y chromosome diversity. An estimate of 142 KY was obtained for the coalescence time of the revised MSY tree, which is earlier than that obtained in previous studies and easier to reconcile with plausible scenarios of modern human origin. The number of deep branchings leading to African-specific clades has doubled, further strengthening the MSY-based evidence for a modern human origin in the African continent. An analysis of 2204 African DNA samples showed that the deepest clades of the revised MSY phylogeny are currently found in central and northwest Africa, opening new perspectives on early human presence in the continent.
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Quote:
The deepest branching separates A1b from a monophyletic clade whose members (A1a, A2, A3, B, C, and R) all share seven mutually reinforcing derived mutations (five transitions and two transversions, all at non-CpG sites). To retain the information from the reference MSY tree13 as much as possible, we named this clade A1a-T (Figure 1). Within A1a-T, the transversion V221 separates A1a from a monophyletic clade (called A2-T) consisting of three branches: A2, A3, and BT, the latter being supported by ten mutations (Figure 1).
--Fulvio Cruciani et al
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A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa
An African American Paternal Lineage Adds an Extremely Ancient Root to the Human Y Chromosome Phylogenetic Tree
Fernando L. Mendez, Thomas Krahn, Bonnie Schrack, Astrid-Maria Krahn, Krishna R. Veeramah, August E. Woerner, Forka Leypey Mathew Fomine, Neil Bradman, Mark G. Thomas, Tatiana M. Karafet, Michael F. Hammer
DOI: dx.doi.org/10.1016/j.ajhg.2013.02.002 |
We report the discovery of an African American Y chromosome that carries the ancestral state of all SNPs that defined the basal portion of the Y chromosome phylogenetic tree. We sequenced ~240 kb of this chromosome to identify private, derived mutations on this lineage, which we named A00. We then estimated the time to the most recent common ancestor (TMRCA) for the Y tree as 338 thousand years ago (kya) (95% confidence interval = 237–581 kya). Remarkably, this exceeds current estimates of the mtDNA TMRCA, as well as those of the age of the oldest anatomically modern human fossils. The extremely ancient age combined with the rarity of the A00 lineage, which we also find at very low frequency in central Africa, point to the importance of considering more complex models for the origin of Y chromosome diversity. These models include ancient population structure and the possibility of archaic introgression of Y chromosomes into anatomically modern humans. The A00 lineage was discovered in a large database of consumer samples of African Americans and has not been identified in traditional hunter-gatherer populations from sub-Saharan Africa. This underscores how the stochastic nature of the genealogical process can affect inference from a single locus and warrants caution during the interpretation of the geographic location of divergent branches of the Y chromosome phylogenetic tree for the elucidation of human origins
Fulvio Cruciani, Beniamino Trombetta, Andrea Massaia, Giovanni Destro-Bisol, Daniele Sellitto, Rosaria Scozzari
DOI: dx.doi.org/10.1016/j.ajhg.2011.05.002
To shed light on the structure of the basal backbone of the human Y chromosome phylogeny, we sequenced about 200 kb of the male-specific region of the human Y chromosome (MSY) from each of seven Y chromosomes belonging to clades A1, A2, A3, and BT. We detected 146 biallelic variant sites through this analysis. We used these variants to construct a patrilineal tree, without taking into account any previously reported information regarding the phylogenetic relationships among the seven Y chromosomes here analyzed. There are several key changes at the basal nodes as compared with the most recent reference Y chromosome tree. A different position of the root was determined, with important implications for the origin of human Y chromosome diversity. An estimate of 142 KY was obtained for the coalescence time of the revised MSY tree, which is earlier than that obtained in previous studies and easier to reconcile with plausible scenarios of modern human origin. The number of deep branchings leading to African-specific clades has doubled, further strengthening the MSY-based evidence for a modern human origin in the African continent. An analysis of 2204 African DNA samples showed that the deepest clades of the revised MSY phylogeny are currently found in central and northwest Africa, opening new perspectives on early human presence in the continent.
---------------------
Quote:
The deepest branching separates A1b from a monophyletic clade whose members (A1a, A2, A3, B, C, and R) all share seven mutually reinforcing derived mutations (five transitions and two transversions, all at non-CpG sites). To retain the information from the reference MSY tree13 as much as possible, we named this clade A1a-T (Figure 1). Within A1a-T, the transversion V221 separates A1a from a monophyletic clade (called A2-T) consisting of three branches: A2, A3, and BT, the latter being supported by ten mutations (Figure 1).
--Fulvio Cruciani et al
======================================================
A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa
An African American Paternal Lineage Adds an Extremely Ancient Root to the Human Y Chromosome Phylogenetic Tree
Fernando L. Mendez, Thomas Krahn, Bonnie Schrack, Astrid-Maria Krahn, Krishna R. Veeramah, August E. Woerner, Forka Leypey Mathew Fomine, Neil Bradman, Mark G. Thomas, Tatiana M. Karafet, Michael F. Hammer
DOI: dx.doi.org/10.1016/j.ajhg.2013.02.002 |
We report the discovery of an African American Y chromosome that carries the ancestral state of all SNPs that defined the basal portion of the Y chromosome phylogenetic tree. We sequenced ~240 kb of this chromosome to identify private, derived mutations on this lineage, which we named A00. We then estimated the time to the most recent common ancestor (TMRCA) for the Y tree as 338 thousand years ago (kya) (95% confidence interval = 237–581 kya). Remarkably, this exceeds current estimates of the mtDNA TMRCA, as well as those of the age of the oldest anatomically modern human fossils. The extremely ancient age combined with the rarity of the A00 lineage, which we also find at very low frequency in central Africa, point to the importance of considering more complex models for the origin of Y chromosome diversity. These models include ancient population structure and the possibility of archaic introgression of Y chromosomes into anatomically modern humans. The A00 lineage was discovered in a large database of consumer samples of African Americans and has not been identified in traditional hunter-gatherer populations from sub-Saharan Africa. This underscores how the stochastic nature of the genealogical process can affect inference from a single locus and warrants caution during the interpretation of the geographic location of divergent branches of the Y chromosome phylogenetic tree for the elucidation of human origins