Human paternal and maternal demographic histories: insights from high-resolution Y chromosome and mtDNA sequences.
Level 4 - case-series / case-control
Cross-sectional population genomic sequencing study
PubMed 25254093 · doi:10.1186/2041-2223-5-13
What was done
Researchers sequenced approximately 500 kb of non-recombining Y chromosome (NRY) sequence using a capture array enrichment method and sequenced complete mitochondrial DNA (mtDNA) genomes in 623 males from 51 populations in the CEPH Human Genome Diversity Panel (HGDP). They analyzed sex-biased demographic histories and ancestral population parameters using model-based simulations.
What was found
Sequencing identified 2,228 SNPs in NRY and 2,163 SNPs in mtDNA. Global genetic differentiation between human populations was larger for NRY than mtDNA, with substantial regional variation. Model-based simulations estimated ancestral effective population sizes of <100 during the out-of-Africa migration and for several regional human populations. The ratio of female to male effective population size (Nf/Nm) was greater than 1 throughout modern human history and has increased recently due to faster growth in female effective population size.
Why it matters
Using direct high-resolution sequencing for both maternal and paternal markers eliminates ascertainment bias present in older genotyping studies, providing clearer baseline estimates for sex-biased migration, residence patterns, and demographic expansion in human history.
Limits
The total sample of 623 individuals is divided across 51 populations, yielding small sample sizes per individual group. Ancestral effective population sizes and demographic growth trajectories are inferred through computational models and simulations rather than direct observation. The study is limited to samples available within the HGDP repository.