Mutations
Define missense, nonsense, and silent
Missense: changes the amino acid in the amino acid sequence
Nonsense: introduces an early stop codon
Silent: does not alter the resulting protein
Define mean and provide the equation for solving for it
A measure of central tendency
Quantitative characteristics often exhibit a _________________ distribution
normal
What does broad sense solve for? What does narrow sense solve for?
Broad sense: proportion of the phenotypic variance due to genetic variance
Narrow sense: proportion of the phenotypic variance due to additive genetic variance (measure of resemblance)
What is the equation used to find how many chromosomes would be found in nullisomy, monosomy, trisomy, and allotriploid? Solve for a diploid individual with
2n = 36
2n-2 = 34
2n-1 =35
2n+1 =37
3n = 54
n=18
When a deletion chromosome pairs with a normal chromosome during prophase I, it is the deletion chromosome that loops out.
False
Define variance and supply the equation for solving for it
A measure of the width of the distribution.
What are the three types of quantitative traits discussed in class and an example of each?
1. Continuous - height
2. Meristic - litter size
3. Threshold - type 2 diabetes
Given the following values, calculate narrow sense heritability:
Additive genetic variance = 78
Dominance genetic variance = 30
Gene interaction variation = 15
Environmental variance = 200
Genetic-environmental interaction variance = 6
0.24
What is the outcome of a Robertsonian Translocation?
"New" metacentric chromosome and a short fragment that is often lost
What type of mutation is occurring in the chromosome segment below:
A B * C D E F G -----> A B * C D G F E
paracentric inversion
5 caterpillars were measured. Their lengths (in cm) were
7, 9, 6, 11, 8
Calculate the mean
8.2 cm
In a watermelon population, the number of seeds is determined by four genes (A, B, C, and D genes) of equal effect that act additively. A dominant allele contributes 30 seeds, and a recessive allele contributes 10 seeds. In this population, watermelons with genotypes AabbCCDd and aaBbCcDD have the same number of seeds.
True
The narrow-sense heritability in sheep is 0.42. The phenotypic variance is 0.73, and the environmental variance is 0.25. What is the additive genetic variance?
0.31
Species I has 2n = 42 chromosomes and species II has 2n = 38. How many chromosomes would be found in an allotriploid of these species?
59 or 61
What type of mutation occurred below? Be as specific as possible
GGG GCT ATA CGT
GGG GCT ATA GGT
Single base substitution, transversion
5 caterpillars were measured. Their lengths (in cm) were
7, 9, 6, 11, 8
Calculate the variance
3.7
Bat wingspan is determined by 6 genes. Bats that are homozygous for all recessive alleles have a wingspan of 3 in. Bats that are homozygous for all dominant alleles have a wingspan of 6 in. What is the wingspan of a bat with the genotype AaBBCcDdEEff?
4.75 in
The phenotypic variance for an outbred strain of frogs is 634. The phenotypic variance for an inbred strain of frogs is 271. What is the broad sense heritability and interpret the value.
0.57
Explain the mechanism that causes Familial Down Syndrome
Robertsonian translocation between chromosomes 14 and 21
In one species of dogs, chromosome I has the segments ABCDEFG and chromosome V has the segments LMNOPQR. If one dog of this species has chromosomes ABCDPQR and LMNOEFG, what type of mutation occurred?
reciprocal translocation
5 caterpillars were measured. Their lengths (in cm) were
7, 9, 6, 11, 8
Calculate the standard deviation
1.92
Tomato weight is determined by 2 independently assorting loci. The dominant allele contributes 3 g to plant weight and the recessive allele contributes 0.5 g. What will be the most frequent weight of tomatoes in the F2 generation?
7g
The broad sense heritability of bat’s wing span was calculated to be 0.45. If the phenotypic variance was 273, what is the genetic variance?
122.85
What are the two methods for mapping quantitative traits discussed in lecture?
QTL mapping (Quantitative Trait Loci)
GWAs (genome-wide association studies)