Volume 10 - Article 7 | Pages 171–196  

Tracing very long-term kinship networks using SOCSIM

By Mike Murphy

Abstract

While each individual has 10 billion ancestors a thousand years ago, these are not distinct and in practice, the number of distinct ancestors is much smaller. A female (‘mitochondrial Eve’) and a male ancestor (‘Y-chromosome Adam’) of all humans certainly existed, possibly about 100,000 years ago, and a most recent common ancestor (MRCA) of all humans existed much more recently.
I use the SOCSIM micro simulation program to estimate the patterns of descent over periods of several centuries, using as indicators,:the proportion of people without any living descendants; the mean number of distinct descendants; and the genetic contribution to later populations. About three quarters of those born in the past have no descendant, mainly because they did not reach the age of reproduction.
After about 500 years, the number of descendants with the populations sizes used her, about 4,000, the number of descendants becomes very similar and close to the size of the number of descendants, confirming that even in these timescale, in the past, a person is either the ancestor of everyone, or of no-one. However, the genetic contribution does not exhibit a similar tendency to uniformity. Issues such as the relevant measures of generational replacement to cases with multiple lines of descent are also considered.

Author's Affiliation

• Mike Murphy - London School of Economics and Political Science, United Kingdom EMAIL

Most recent similar articles in Demographic Research

The formal demography of kinship VI: Demographic stochasticity and variance in the kinship network
Volume 51 - Article 39    | Keywords: dependency ratios, kinship, matrix models, multitype branching processes, prevalence, stochastic models

The formal demography of kinship V: Kin loss, bereavement, and causes of death
Volume 49 - Article 41    | Keywords: bereavement, causes of death, competing risks, kin loss, kinship, matrix models

The formal demography of kinship IV: Two-sex models and their approximations
Volume 47 - Article 13    | Keywords: female fertility, kinship, male fertility, matrix models, sex ratio, two-sex models

“One hand does not bring up a child:” Child fostering among single mothers in Nairobi slums
Volume 46 - Article 30    | Keywords: child fostering, informal settlements, Kenya, kinship, single motherhood, sub-Saharan Africa

National estimates of kinship size and composition among adults with activity limitations in the United States
Volume 45 - Article 36    | Keywords: caregiving, disability, family, kinship