Chapter 8 Flashcards
Evolution at Multiple Loci: Linkage and Sex
A haplotype is best defined as
Multilocus genotype of a chromosome or gamete
Which of the following statements regarding linkage equilibrium is true?
Is reduced by sexual reproduction
When two loci are in linkage equilibrium, the allele carried on a chromosome at one locus is independent of the allele carried on the chromosome at another locus. When this is the case
The frequency of each haplotype can be calculated by multiplying the frequency of its two alleles allele frequencies will not change over time
Selection on multilocus genotypes in random-mating populations leads to linkage disequilibrium when
Some allele combinations confer greater fitness than do others
By breaking up overrepresented haplotypes and creating new ones, _______________ reduces linkage disequilibrium.
Genetic recombination, crossing over, sexual reproduction
Which of the following statements regarding linkage disequilibrium between Ashkenazi disease alleles and nearby marker loci are true?
Appears due to genetic drift, associated with three periods of founder effects
Decays at a rate determined by crossing-over between the two loci.
Can be used to estimate the age of the most recent common ancestor of each allele
Two lessons of two locus Hardy-Weinberg analysis:`
- Populations can have identical allele frequencies but different chromosome frequencies.
2.
When we use population genetics models to analyze evolution at a particular locus, do we need to worry about the effects of selection at other loci?
Only if the locus of interest and the other loci are in linkage disequilibrium
What is linkage equilibrium?
When the genotxtype of a chromosome at one locus is independent of its genotype at the other locus
What is linkage disequilibrium?
When there is a nonrandom association between a chromosomes;s genotype at one locus and its genotype at the other locus
