Chapter 5

Question 1

Dominance relationship in which the heterozygous phenotype is the same as the phenotype for one of the homozygotes

Answer 1

Complete Dominance

Question 2

Dominance relationship in which the heterozygous phenotype is intermediate between the two homozygous phenotypes

Answer 2

Incomplete Dominance

Question 3

Dominance relationship in which the heterozygous phenotype includes both of the homozygous phenotypes

Answer 3

Codominance

Question 4

The percentage of a population with a particular genotype that shows the expected phenotype

Answer 4

Penetrance

Question 5

The degree or intensity with which a particular genotype is expressed in a phenotype

Answer 5

Expressivity

Question 6

The multiple alleles of a gene that can exist

Answer 6

Allelic Series

Question 7

A mutation that causes the function of a gene product to be completely abolished

Answer 7

Null Mutation

Question 8

A mutation that causes the function of a gene product to be partially abolished

Answer 8

Hypomorphic Mutation

Question 9

A mutation that causes the function of the gene product to be increased or expressed in ectopic sites in the body

Answer 9

Hypermorphic Mutations

Question 10

When one gene affects multiple characteristics that may or may not be obviously related to each other

Answer 10

Pleiotropy

Question 11

A type of allele that has usually has recessive inheritance and can be detected as a distortion in the phenotypic segregation ratios (e.g. 2:1 segregation) caused by one or more missing classes of viable progeny

Answer 11

Lethal Alleles

Question 12

A test that compares how well the observes results fit the expected results

Answer 12

Chi-square goodness-of-fit test

Question 13

The hypothesis that any deviation between the observed and expected values is the result of chance

Answer 13

Null Hypothesis

Question 14

The number of outcome classes minus 1 (n-1)

Answer 14

Degrees of Freedom

Question 15

The probability that the deviation from expected numbers had occurred by chance

Answer 15

P-value

Question 16

Conditions for rejecting the null hypothesis

Answer 16

P < 0.05

Question 17

Conditions for not rejecting the null hypothesis

Answer 17

P > 0.05

Question 18

When an allele of one gene modifies or prevents the phenotype caused by alleles of another gene

Answer 18

Epistasis

Question 19

The overriding gene/allele is ___ to the masked gene/allele

Answer 19

Epistatic

Question 20

The masked gene/allele is ___ to the overriding gene/allele

Answer 20

Hypostatic

Question 21

When recessive alleles of one gene mask the phenotype caused by alleles of another gene (9:3:4 ratio)

Answer 21

Recessive Epistasis

Question 22

When dominant alleles of two genes act together to product wildtype phenotype (9:7 ratio), homozygous recessive for either gene results in the same phenotype as homozygous for both genes

Answer 22

Duplicate Recessive Epistasis

Question 23

When the phenotypes of the mutant parents are caused by mutations in two different genes, is observed in progeny of individuals with mutations in different genes

Answer 23

Genetic Complementation

Question 24

Traits that have the same phenotype but are caused by mutations in different genes

Answer 24

Heterogenous traits

Question 25

Traits in which inheritance is autosomal but the trait only appears in one sex, results from sex-limited expression of autosomal genes

Answer 25

Sex-limited Traits

Question 26

Traits in which the inheritance is autosomal but is much more frequent in one sex, results from expression of autosomal genes being influenced by hormones that differ between the sexes

Answer 26

Sex-influenced traits

Question 27

When a trait becomes more severe or is expressed at an earlier age at succeeding generations, most often seen in disorders of the nervous system in humans, usually because of unstable size of repeat sequences in or near genes, also seen in syndromes associated with progressive telomere shortening

Answer 27

Genetic Anticipation

Question 28

When environmental factors alone produce a phenotype that is identical to a phenotype caused by a genotype

Answer 28

Phenocopy

Question 29

Characteristics that possess only a few easily distinguishable phenotypes

Answer 29

Discontinuous (qualitative) Characteristics

Question 30

Characteristics that vary along a scale of measurement with many overlapping phenotypes, often polygenic and multifactorial

Answer 30

Continuous (Quantitative) Characteristics

Question 31

Caused by the combined effect of multiple genes

Answer 31

Polygenic

Question 32

Affected by multiple genes and the environment

Answer 32

Multifactorial