Exam 4 Vocab and Multiple Choice Flashcards
correlation
the strength of association between two measurements
quantitative
a trait that is continuously variable over some measure
inbreeding
preferential mating between related individuals
regression
linear relationship between two variables
allopatric
speciation is initiated when a geographic barrier splits a population into two or more groups
variance
indicates the variability of a group of measurements
bottleneck
when a population undergoes a drastic reduction in size
mean
provides information about the center of the distribution
positive assortative mating
tendency for like individuals to mate
founder effect
establishment of a population by a small number of individuals
sympatric
speciation arises in the absence of an geographic barrier to gene flow
qualitative
a trait with only a few distinctive phenotypic classes
One can estimate the number of genes underlying a trait by crossing two pure lines where the parents are extreme for the phenotype of interest. For example one parent is extremely small and the other parent is extremely large where it is assumed that the small parent is homozygous for all the “small” alleles and offspring will all be heterozygous. If one then intercrosses the F1 to produce the F2, the proportion of the F2 that resemble the parents phenotype is an estimate of the number of genes involved. If one did this experiment and found that 1/4096 offspring resembles the parents, how many loci are involved in determining the phenotype?
A) 2
B) 3
C) 5
D) 4
E) none of the above
E) none of the above (n=6)
assuming a trait has a high narrow sense of heritability, which relationships would you expect to be most similar phenotype of the trait?
A) fullsibs
B) half sibs
C) 1st degree cousins
D) they’re all very different
A) full sibs
bristle number in drosophila is a highly heritable trait with h^2 = 0.52. If the average bristle number in the parental population was 28.7 and you selected flies to produce the next generation that had mean bristle number of 30.5, what is the selection differentials?
a) -1.8
b) 43.6
c) 1.8
d) none of the above
c) 1.8
A particular location on a chromosome, say chromosome 1 position 120,256,947 bp, has 3 alleles (A, C, and T) segregating in the population. If the frequency of allele A is 0.70, what if the frequency of the T allele?
a) 0.80
b) 0.20
c) 0.70
d) unable to tell base on the information given
d) unable to tell base on the information given
What are the 5 main assumptions for a population to be in the Hardy-Weinberg Equilibrium?
- random mating
- no mutation
- no migration
- no selection
- no drift (large population size)
If the Hardy-Weinberg Equilibrium assumptions are met, what two predictions can be made in a population in equilibrium?
- allele frequencies do not change
- equilibrium will be reached in one generation
sampling error arises when gametes unite to produce progeny. The variance in allelic frequency at a locus is determined by the frequency of the alleles at that locus. Which of the following loci will have the largest variance in allele frequency?
a) locus 1 where p=0.40
b) locus 2 where p=0.70
c) locus 3 where p=0.30
d) unable to determine with the information provided
a) locus 1 where p=0.40
what is the expected frequency of heterozygosity in a population with allelic frequencies represented by variables x any y that is in the Hardy-Weinberg equilibrium?
a) x+y
b) (x+y)^2
c) xy
d) xy/2
e) none of these
e) none of these (2xy)
In cats, all-white color is dominant over colors other than all-white. In a population of 100 cats, 75 are all-white. Assuming that the population is in the Hardy-Weinberg equilibrium, what is the expected frequency of all-white cats homozygous for the all-white allele in this population?
a) 0.50
b) 0.25
c) 0.75
d) 0.125
e) none of these
b) 0.25
When a population is in mutational equilibrium, which of the following is true?
a) the number of forward mutations is greater than the number of reverse mutations
b) the number of forward mutations is equal to the number of reverse mutations
c) no forward or reverse mutations occur
d) the population is in the HWE
e) none of these are true
f) two of these are true
b) the number of forward mutations is equal to the number of reverse mutations
consider two large populations (A & B) and a bi-allelic locus with alleles at frequency p and q. In one generation, 10 random individuals migrate from population A to population B. What will happen to the allele frequency q as a result of migration when q is equal in both populations?
a) q in population A will decrease
b) q in population B will increase
c) q will not change in either population A or B
d) q in population B will become q^2
e) not enough information provided to answer correctly
c) q will not change in either population A or B
