Topic 4B

Question 1

quantitative traits

Answer 1

phenotype of complex traits that can be measured (along a continuum with only small intervals between similar individuals)

Question 2

environmental risk factor

Answer 2

a characteristic in a person’s surroundings that increases the likelihood of developing a particular disease

Question 3

inbred lines

Answer 3

true breeding strains (often used for research)-genetically identical and same environmental factors, but can still have varied phenotypes

Question 4

normal distribution

Answer 4

approximation of distribution of phenotypes by a bell-shaped curve

Question 5

the term complex trait implies that:

Answer 5

both genetic factors and environmental factors contribute to variation in phenotype among individuals

Question 6

it is possible to separate genes and environment in regard to their:

Answer 6

effects on the differences, or variation, among individuals within a particular population

Question 7

norm of reaction

Answer 7

graphically depicts how the environment (x-axis) affects phenotype (y-axis) for any genotype across a range of environments

Question 8

genotype-by-environment interaction

Answer 8

implies that the effect of a genotype cannot be specified without knowing the environment and the other way around; phenotype depends on both genotype and environment in complex traits

Question 9

population genetics

Answer 9

the study of patterns of genetic variation

Question 10

species

Answer 10

individuals that can exchange genetic material through interbreeding, i.e. of sharing alleles with one another through reproduction

Question 11

individuals represent:

Answer 11

different combinations of alleles drawn from the specie’s gene pool

Question 12

gene pool

Answer 12

all the alleles present in all individuals in the species

Question 13

populations

Answer 13

interbreeding groups of organisms of the same species living in the same geographical area

Question 14

what are the two sources of genetic variation?

Answer 14

mutation and recombination (followed by segregation of homologous chromosomes)-both forms new alleles

Question 15

somatic mutations

Answer 15

occurs in body tissues

Question 16

germline mutation

Answer 16

occurs in reproductive cells and can be passed on to the next generation

Question 17

neutral mutation

Answer 17

having little or no effect on an organism

Question 18

deleterious mutation

Answer 18

harmful effect on an organism

Question 19

advantageous mutation

Answer 19

improves carriers’ chances of survival or reproduction

Question 20

allele frequencies

Answer 20

rate of occurrence of alleles in populations; provides a measure of genetic variation at one gene in a given population

Question 21

if a population is FIXED for an allele, it means that:

Answer 21

the population only exhibits that one allele, the allele frequency is 100%

Question 22

what are three ways to measure genotype and allele frequency in populations?

Answer 22

observable traits, gel electrophoresis, and DNA sequencing

Question 23

evolution is a change in:

Answer 23

allele or genotype frequency over time

Question 24

Hardy-Weinberg equilibrium

Answer 24

describes situations in which allele and genotype frequencies do not change; i.e. in which evolution does not occur

Question 25

what are the conditions of the Hardy-Weinberg equilibrium?

Answer 25

1. There can be no differences in the survival and reproductive success of individuals
2. populations must not be added to or subtracted from by migration
3. there can be no mutation
4. the population must be sufficiently large to prevent sampling errors
5. individuals must mate at random