Module 11 Genetic Variation

Question 1

Branch of biology concerned with heredity and variation

Answer 1

Genetics

Question 2

branch of genetics which deals with the behavior of genes in population and studies polymorphism and divergence.

Answer 2

Population Genetics

Question 3

genetic heterogeneity in a population

enables the species to adapt to future novel changes in the environment

raw material for evolution

Answer 3

Genetic Variation

Question 4

How is genetic variation measured?

Answer 4

*univariate and multivariate statistics

*use of isozymes

*use of other genetic markers such as RAPDs, RFLP, AFLP, minisatellites, microsatellites, SNPs, CNVs, DNA sequences of mtDNA and nuclear markers

Question 5

functionally similar but separable forms of enzymes encoded by one or more loci

Answer 5

Isozymes

Question 6

When doing isozyme analysis, you observe three banding patterns. The first has one band at the bottom, the second has one band at the top, the third has one band at the top and one at the bottom. What does this mean?

Answer 6

There are fast and slow alleles. The smaller or “fast” allele is at the bottom, the larger or “slow” allele is at the top. The presence of both mean it is heterozygous. Since there is no intermediate bands between the two, it is monomeric. (See slide 11 of lecture 11)

Question 7

When doing isozyme analysis, you observe three banding patterns. The first has one band at the bottom, the second has one band at the top, the third has one band at the top, one at the bottom with both being barely distinct, and a band or multiple bands between the top and bottom. What does this mean?

Answer 7

The enzyme is dimeric. The top is the slow allele, the bottom is the fast allele, the in between bands are the heterozygote mixes.

Question 8

This is the % of loci or nucleotide positions showing more than one allele or base pair

Answer 8

Polymorphism

Question 9

This is the % of individuals that are heterozygotes

Answer 9

Heterozygosity (H)

Question 10

This is the measure of # and diversity of different alleles or haplotypes within a population

Answer 10

Allele/Haplotype Diversity

Question 11

This is the measure of number and diversity of variable nucleotide positions within sequences of a population

Answer 11

Nucleotide Diversity

Question 12

This is the measure of number of base pairs between two homologous sequences

Answer 12

Genetic Distance

Question 13

This is the % of nucleotide substitutions that result in amino acid replacement

Answer 13

Nonsynonymous substitutions

Question 14

This is the % of nucleotide substitutions that don’t result in amino acid replacement

Answer 14

Synonymous substitutions

Question 15

How do you calculate intrapopulation nucleotide diversity?

Answer 15

πx = (n/(n-1)) * ∑(XiXjπij)

Where:

n = sample size

πx = the average weighted sequence divergence between haplotypes

Xi = is the rel. freq. of seq i

Xj = is the rel. freq. of seq. j

πij = count of differences between sequences i and j (i can have an A in the same position where j has a G, etc.)

Question 16

Intrapopulation Nucleotide Diversity (πx) ranges from 0 to 1. What does it signify?

Answer 16

• tells about the degree of nucleotide diversity among several sequences in a given region of the genome
• equivalent to the measure of allelic diversity within a locus

Question 17

How do you calculate haplotype diversity (H)

Answer 17

H = (n/(n-1))(1- ∑((xi)^2))

Where:

H = Haplotype Diversity
n = Sample Size
xi = relative haplotype frequence of each haplotype

Question 18

When interpreting haplotype (H) and nucleotide (π) diversities, it can either be small (H<0.5; π<0.5%) or large (H≥ 0.5; π≥0.5%). What does it mean if both H and π are small?

Answer 18

Recent population bottleneck.

Founder event by a single or few mtDNA lineages

Question 19

When interpreting haplotype (H) and nucleotide (π) diversities, it can either be small (H<0.5; π<0.5%) or large (H≥ 0.5; π≥0.5%). What does it mean if both H and π are large?

Answer 19

Large stable population with long evolutionary history

Secondary contact between differentiated lineages

Question 20

When interpreting haplotype (H) and nucleotide (π) diversities, it can either be small (H<0.5; π<0.5%) or large (H≥ 0.5; π≥0.5%). What does it mean if H is small and π is large?

Answer 20

Divergence between geographically subdivided populations

Question 21

When interpreting haplotype (H) and nucleotide (π) diversities, it can either be small (H<0.5; π<0.5%) or large (H≥ 0.5; π≥0.5%). What does it mean if H is large and π is small?

Answer 21

Population bottleneck followed by rapid population growth and accumulation of mutations

Question 22

A hypothetical population consists of 1000 individuals. The genotypic frequencies for the MN blood typing of the population are as follows:

MM: 300
MN: 600
NN: 100

Compute for relative and allelic frequencies

Answer 22

Given:
MM=300, MN=600, NN = 100

Required: Rel and Allele Freq.

Solution:
Rel Freq.=n/N where n count of each, N is the total
MM = 0.3, MN = 0.6, NN = 0.1

Allele Freq. = Frequency of M and N separately. Calc by
(2(Freq of Homozygote)+Freq of Heterozygote)/(2total number of individuals)

M = (2(300)+600)/(21000)=0.6
N = (2(100)+600)/(21000)=0.4

Question 23

I found a blank card so idk, drink water ig