BIOL 206 EVOLUTIONARY GENETICS TEST NOTES (WEEK
5-8) QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+||BRAND NEW
Genetic Linkage Correct Answers all of the genes on a given
chromosome are said to be linked or belong to the same linkage group
(transmitted through meiosis together)
linkage equilibrium Correct Answers -The association of two alleles at
two or more loci at the frequency predicted by their individual
frequencies (PA1B1=PA1XPB1)
-random association of alleles at two or more loci
Loci located farther apart are Correct Answers less linked
Loci that are adjacent to each other are Correct Answers tightly
physically linked
The probability of loci being swapped by recombination depends on the
Correct Answers distance between them
if loci are on the exact opposite ends of the chromosome then the loci
usually recombine at a rate of Correct Answers c=0.5 (all gametes are
equally likely)
if loci are so closely linked that recombination never occurs, then
Correct Answers c=0 (min possible value, alleles are inherited together)
,linkage disequilibrium (D) Correct Answers relationship between the
alleles at different loci; this may be due to physical genetic linkage
(PA1B1 does not equal PA1XPB1)
Haplotype Correct Answers multilocus genotype of a chromosome or
gamete, tend to be inherited together (e.g. PA2B1)
in terms of linkage disequilibrium zero means Correct Answers no
linkage disequilibrium (fully recombinates)
in terms of linkage disequilibrium positive means Correct Answers
excess of A1B1 and A2B2
in terms of linkage disequilibrium negative means Correct Answers
excess of A1B2 and A2B1
How to calculate linkage disequilibrium Correct Answers D=PA1B1-
(PA1XPB1)
What eliminates linkage disequilibrium from a population? Correct
Answers -linkage is broken down by recombination over time
-crossing over during meiosis breaks up old combinations of alleles and
creates new combinations
-process of breaking alleles up takes more than a single generation
, causes of linkage disequilibrium Correct Answers -physical linkage of
locus A and B on the same chromosome
-natural selection (favors AB combos)
-gene flow (AABB individuals arrive in aabb populations)
-assortative mating (AB and AB mate, ab and ab mate)
Why is studying linkage disequilibrium useful? Correct Answers -
migrating patterns
-reconstructing the history of genes
-identifying alleles under selection
-mapping of genes underlying traits of interest (magnitude of effects and
location on genome)
Quantitative trait locus (QTL) Correct Answers region of the genome
that is correlated with a variation in a phenotypic trait, uses an
experimental cross to create linkage disequilibrium
Genome Wide Association Studies (GWAS) Correct Answers looks for
correlations between the genotypes at genetic markers and phenotypic
traits, need very large sample sizes
Broad sense sex Correct Answers genetic material from different
ancestors brought together in a single descendent (mixture of genes)
Strictest sense sex Correct Answers -eukaryotic haploid-diploid cycle
5-8) QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+||BRAND NEW
Genetic Linkage Correct Answers all of the genes on a given
chromosome are said to be linked or belong to the same linkage group
(transmitted through meiosis together)
linkage equilibrium Correct Answers -The association of two alleles at
two or more loci at the frequency predicted by their individual
frequencies (PA1B1=PA1XPB1)
-random association of alleles at two or more loci
Loci located farther apart are Correct Answers less linked
Loci that are adjacent to each other are Correct Answers tightly
physically linked
The probability of loci being swapped by recombination depends on the
Correct Answers distance between them
if loci are on the exact opposite ends of the chromosome then the loci
usually recombine at a rate of Correct Answers c=0.5 (all gametes are
equally likely)
if loci are so closely linked that recombination never occurs, then
Correct Answers c=0 (min possible value, alleles are inherited together)
,linkage disequilibrium (D) Correct Answers relationship between the
alleles at different loci; this may be due to physical genetic linkage
(PA1B1 does not equal PA1XPB1)
Haplotype Correct Answers multilocus genotype of a chromosome or
gamete, tend to be inherited together (e.g. PA2B1)
in terms of linkage disequilibrium zero means Correct Answers no
linkage disequilibrium (fully recombinates)
in terms of linkage disequilibrium positive means Correct Answers
excess of A1B1 and A2B2
in terms of linkage disequilibrium negative means Correct Answers
excess of A1B2 and A2B1
How to calculate linkage disequilibrium Correct Answers D=PA1B1-
(PA1XPB1)
What eliminates linkage disequilibrium from a population? Correct
Answers -linkage is broken down by recombination over time
-crossing over during meiosis breaks up old combinations of alleles and
creates new combinations
-process of breaking alleles up takes more than a single generation
, causes of linkage disequilibrium Correct Answers -physical linkage of
locus A and B on the same chromosome
-natural selection (favors AB combos)
-gene flow (AABB individuals arrive in aabb populations)
-assortative mating (AB and AB mate, ab and ab mate)
Why is studying linkage disequilibrium useful? Correct Answers -
migrating patterns
-reconstructing the history of genes
-identifying alleles under selection
-mapping of genes underlying traits of interest (magnitude of effects and
location on genome)
Quantitative trait locus (QTL) Correct Answers region of the genome
that is correlated with a variation in a phenotypic trait, uses an
experimental cross to create linkage disequilibrium
Genome Wide Association Studies (GWAS) Correct Answers looks for
correlations between the genotypes at genetic markers and phenotypic
traits, need very large sample sizes
Broad sense sex Correct Answers genetic material from different
ancestors brought together in a single descendent (mixture of genes)
Strictest sense sex Correct Answers -eukaryotic haploid-diploid cycle
