Quest 4: Chp 9 Flashcards
(18 cards)
Compensatory mutation
develops after a resistance mutation and strengthens resistance
Polygenic traits
trait influenced by multiple genes; demonstrate near continuous variation
Additive genetic effects
creates near continuous variation; combination of alleles creates different phenotypes
Latent variation
a new assortment of previously occurring mendelian variation when multiple genes control one trait, not new
Haplotype
a set of alleles that are inherited on the same chromosome together
Genotype
the allele identity of the whole organism
Linkage disequilibrium
nonrandom association of alleles at different loci in a population
Coefficient of Linkage Disequilibrium
D = actual haplotype frequency - expected haplotype frequency
Linkage equilibrium
genotype of a chromosome at one locus is independent of its genotype at another locus
If D = 0
alleles are in linkage EQUILIBRIUM
Four causes of Linkage disequilibrium
1) new mutation introduces new haplotype
2) selection on allele combination
3) Migration introduces new haplotype
4) Drift in a small population causes loss of haplotype
Coefficient of recombination
r - higher value means a smaller number of generations required to completely disrupt linkage disequlibrium
Epistasis
two or more alleles interact in non-additive ways; one can mask the other
physical linkage
when loci are close together on the same chromosome and segregate together
Genetic hitchhiking
allele frequency increases due to its linkage disequilibrium with an allele that is selected for
Background selection
loss of surrounding alleles when a deleterious mutation is selected against
Genetic Draft
genetic hitchhiking causes neutral allele to follow strong selection on a close allele
Selective sweeps
1 strongly selected for allele brings other alleles with in and cause population to have set of alleles
