Course
Evolution
Study Pack
Set 9 Evolution At Multiple Loci Quantitative Genetics
Question 1
(Multiple Choice)
Free
In cases where selection consistently favors a higher (or lower)value of a trait or phenotype,the result over time is a change in the average value of a trait in the population.This mode of selection is known as ________.
A) directional selection
B) stabilizing selection
C) disruptive selection
D) selection gradient
Answer
Question 2
(Multiple Choice)
Free
When Bradshaw and colleagues investigated the quantitative trait loci (QTL)of two species of Mimulus (Mimulus cardinalis and Mimulus lewisii),they used marker loci as a way to map the QTLs.Their results are shown in the accompanying figure.According to these results,________. 
A) the differences in genotype for the majority of these QTLs explained small amounts of the variations in flower phenotypes for both species
B) some of the QTLs did have pronounced effects on the flowers' phenotypes
C) at least one QTL explained 90% of the phenotypic variance for each species
D) All of the above.
Answer
Question 3
(Multiple Choice)
Free
The fraction known as the broad-sense heritability (where VG = genetic variation,VP = phenotypic variation,and VE = environmental variation)is expressed by ________.
A) VG/VP
B) VG/VG + VE
C) VG/VP + VE
D) VG/VE
E) A and B are both accurate.
Answer