MIGRATION AND GENETIC DRIFT IN HUMAN POPULATIONS.

Area of Science:

• Population Genetics
• Evolutionary Biology
• Demography

Background:

• Classical population genetics models often assume mortality is highest during dispersal and reproduction.
• This assumption is contrary to observed life cycles in humans and many other species where mortality is concentrated early in life.

Purpose of the Study:

• To introduce a novel population genetics model that incorporates pre-migration population regulation.
• To investigate the implications of this model for geographic variation in allele frequencies between newborns and adults.
• To develop new metrics for understanding migration and population structure.

Main Methods:

• Development of a new population genetics model where regulation precedes migration.
• Analysis of geographic variation in allele frequencies for newborns versus adults.
• Introduction of the 'effective migration rate' parameter.

Main Results:

• The model predicts greater geographic variation in allele frequencies among newborns than adults.
• Reduced genetic variance (variance about the current population mean) converges faster than unreduced variance.
• The difference in variation between newborns and adults provides estimates for effective population size and effective migration rate.

Conclusions:

• Distinguishing genetic variation in newborns from adults is crucial for species with human-like life cycles.
• The effective migration rate offers a robust measure of migration's impact, independent of population size.
• The developed model and metrics enhance the study of genetic population structure and evolutionary dynamics.