Generation time and effective population size in Polar Eskimos

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Matsumura, S., Forster, P.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Royal Society of London 2008
• Subjects: Greenland; eskimo*; North Greenland
• Online Access: https://pure.iiasa.ac.at/id/eprint/8577/; https://doi.org/10.1098/rspb.2007.1724

North Greenland Polar Eskimos are the only hunter-gatherer population, to our knowledge, who can offer precise genealogical records spanning several generations. This is the first report from Eskimos on two key parameters in population genetics, namely, generation time (T) and effective population size (N_e). The average mother-daughter and father-son intervals were 27 and 32 years, respectively, roughly similar to the previously published generation times obtained from recent agricultural societies across the world. To gain an insight for the generation time in our distant ancestors, we calculated maternal generation time for two wild chimpanzee populations. We also provide the first comparison among three distinct approaches (genealogy, variance and life table methods) for calculating N_e, which resulted in slightly differing values for the Eskimos. The ratio of the effective to the census population size is estimated as 0.6-0.7 for autosomal and X-chromosomal DNA, 0.7-0.9 for mitochondrial DNA and 0.5 for Y-chromosomal DNA. A simulation of alleles along the genealogy suggested that Y-chromosomal DNA may drift a little faster than mitochondrial DNA in this population, in contrast to agricultural Icelanders. Our values will be useful not only in prehistoric population inference but also in understanding the shaping of our genome today.