Chapter 9: Genetic Variation in Individuals and Populations: Mutation and Polymorphism

Question 1

• affects the number of chromosomes in the cell

- mechanism: chromosome missegregation (aneuploidy)

Answer 1

genome mutation

Question 2

• alter the structure of individual chromosomes

- mechanism: chromosome rearrangement (translocations, inversions, duplications, deletions)

Answer 2

chromosome mutation

Question 3

• alter individual genes ranging from a change in a single nucleotide to changes affecting millions of base paids
• mechanism: base pair mutation (point mutation, small deletion or insertion)

Answer 3

gene mutation

Question 4

mutations that convert amino acid-coding codons into premature stop codons

Answer 4

nonsense mutations

Question 5

mutations convert an amino acid codon into a codon for a different amino acid

Answer 5

missense mutations

Question 6

mutations which alter the codon sequence but NOT the amino acid

Answer 6

silent mutations

Question 7

convert a normal stop codon sequence into an amino acid codon

Answer 7

nonstop mutations

Question 8

addition or deletion where the number of bases is not a multiple of 3

Answer 8

frameshift mutation

Question 9

defined as the occurrence of at least 2 variant alleles at a locus, each found on chromosomes with >1% frequency in the population

Answer 9

genetic polymorphisms

Question 10

defined as the occurrence of at least 2 variant alleles at a locus, each found on chromosomes with <1% frequency in the population

Answer 10

rare variants

Question 11

simplest and most common of all polymorphisms

Answer 11

single nucleotide polymorphisms (SNPs)

Question 12

stretches of DNA consisting of two, three, or four nucleotides repeated between one and a few dozen times

Answer 12

microsatellites

Question 13

Which blood type is due to: an allele that produces a gllycotransferase that adds N-acetylgalactosamine to the H antifen?

Answer 13

Type A

Question 14

Which blood type is due to: a result of a different allele of the same gene that adds a D-galactose to the H antigen?

Answer 14

Type B

Question 15

Which blood type is due to: a result of another allelic form of the gene which does not produce a functional transferase, so no sugar is added to the H antigen?

Answer 15

Type O

Question 16

What does the one gene that produces ABO blood groups encode?

Answer 16

a glycosyltransferase

Question 17

How are A and B alleles inherited? And O?

Answer 17

codominantly; recessively

Question 18

This type of individual produces the Rh D antigen which is encoded by the RHD gene on chromosome 1

Answer 18

Rh positive

Question 19

This type of individual does not express the antigen

Answer 19

Rh negative

Question 20

What are the MHC Class I genes?

Answer 20

HLA-A, HLA-B, HLA-C

Question 21

What are the MHC Class II genes?

Answer 21

HLA-DP, HLA-DQ, HLA-DR

Question 22

the quantitative study of the distribution of genetic variation in populations and of how the frequencies of genes are maintained or changed

Answer 22

population genetics

Question 23

refers to the % of the total alleles in the population with the sum total of various allele frequencies

Answer 23

allele frequency

Question 24

measures the proportion of each genotype in a population

Answer 24

genotype frequency

Question 25

What is the equation for estimation of allele and carrier frequency for autosomal recessive disorders?

Answer 25

q=√I

Question 26

What is the equation for estimation of allele and carrier frequency for autosomal dominant disorders?

Answer 26

q=1/2 x I

Question 27

What is the equation for estimation of allele and carrier frequency for X-linked recessive disorders?

Answer 27

I=q

Question 28

Equation for p?

Answer 28

p=1-q

Question 29

Equation for carrier frequency?

Answer 29

2pq

Question 30

What are the 6 factors that disturb Hardy-Weinberg Equilibrium?

Answer 30

- stratification - assortative mating - consanguinity - mutation and selection - genetic drift - gene flow

Question 31

when a subgroup of a population remains genetically distinct from the rest of the population

Answer 31

stratification

Question 32

a nonrandom mating pattern when a mate is chosen because they possess a particular trait

Answer 32

assortative mating

Question 33

brings about an increase in the frequency of autosomal recessive diseases

Answer 33

consanguinity

Question 34

when a new mutation arises in a population, the fitness of the new allele determines if it will survive and enter the new gene pool

Answer 34

mutation and selection

Question 35

the fluctuation in allele frequency due to chance operating on the small gene pool contained within a small population

Answer 35

genetic drift

Question 36

refers to the slow diffusion of genes across a barrier

Answer 36

gene flow

Question 37

the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population

Answer 37

founder effect

Question 38

What is the wild type (normal) allele?

Answer 38

p

Question 39

What is the homozygous normal genotype?

Answer 39

p squared

Question 40

What is the mutant allele?

Answer 40

q

Question 41

What is the homozygous mutant genotype?

Answer 41

q squared