Drift/Mutation/Flow Flashcards Preview

Human Biology > Drift/Mutation/Flow > Flashcards

Flashcards in Drift/Mutation/Flow Deck (24):
1

The Modern Synthesis

Combined darwins and mendels genetics to see evolution at population level as an explanation of the macro world changes in a micro fashion

2

Muetral Theory of Evolution

Most of the genome is evolutionarialy nuetral (if it doesn;t effect reproduction it is not selected on)

3

Evolution

change in allele frequency over time

4

What are the deterministic forces of evolution (2)?

natural selection and gene flow

5

What are the random forces of evolution (2)?

Mutation and Genetic Drift

6

Genetic Drift

A change in allele frequency due to random sampling of the population

7

What is effect of drift like on small populations?

Large effect

8

What is the result of genetic drift?

Loss in diversity because alleles become fixed

9

How can you estimate the effective population size using drift and mutation rate?

Mutations enter the population at a rate u •Most new mutations are lost, some drift to fixation •Larger Ne = slower drift = more genetic variation (m) in the population at any given time -> If you know u and m, you can calculate Ne
Ne=m/4u
•Ne for the ancestral human population is estimated at 4,600-11,200 people (i.e. reproducing adults)!

10

Gene Flow

Migration resulting in the moving of alleles to a new population

11

What is the result of gene flow?

homogenizes allele frequencies among populations

12

How is gene flow determined?

Based on the number of people migrating to new populations

13

Wrights Fixation Index

Genetic variation among populations/
Genetic variation within populations

14

What does Fst=1 mean?

All the variation is between populations and NONE is within

15

What does large structure in population mean?

This means that the there is less variation within a population

16

Founder Effect results in:

less variation in population the farther away populations move from original source

17

Founder Events+Gene Flow

Create isolation by distance

18

Mutation

Error in DNA synthesis leading to new variation

19

All new genetic variation comes from:

Mutations

20

What is mutation influenced by?

Nothing! It is completely random

21

How can we calculate the number of mutations in population?

Ne times mutation rate times number of generations

22

Haplotype

a set of variants that are inherited as part of the same stretch of DNA

23

Why do we look at haplotypes in Y chromosome?

Because there is no recombination (highly conserved)

24

Molecular Clock

Neutral mutations accumulate at a clock-like rate