Lecture 21. Applied Evolutionary Genetics Flashcards
What do gene trees do not always match ?
Species tree
What is a gene and a species tree that matches called ?
Concordant
What is incomplete lineage sorting ?
If the time between the two divergences is short and the population is large neither allele may reach fixation before the next split
What is another way to describe incomplete lineage sorting ?
Retention of ancestral polymorphism through speciation events
What are gene trees and species trees that do not match called ?
Discordant
What is an example of incomplete lineage sorting ?
Modern and archaic human population
What would prevent the number of discordant gene trees that place non-African with Neanderthal equaling the number that place African with Neanderthal ?
Gene flow has increased the number of gene trees that group Non-African with Neanderthal
What is introgression ?
The transfer of genetic material between species or subspecies through horizontal event followed by backcrossing with the parental species
What can be used to detect and measure gene flow ?
Deviations from simple phylogenetic expectation
Why do present day Eurasians show less Neanderthal ancestry than prehistoric Eurasians ?
Neanderthals carried more deleterious variants due to long-term small population sizes and inbreeding. Neanderthal ancestry was associated with reduced fitness
What are many human diseases caused by ?
Mutations in single genes
What is haploinsufficiency ?
One functional allele insufficient to get the job done
What is dominant negative mutation ?
Faulty protein is produced and interferes with the wildtype allele’s function
Roughly, how many de novo mutations does a newborn carry ?
75
What is a major source of mutation ?
DNA replication
