Genetics 5

Question 1

lethal

Answer 1

any allele that can cause the premature death of the organism; can be due to dominant or recessive allele at any stage of development

Question 2

incomplete dominance

Answer 2

expression of one allele does not completely mask the expression of the second allele

Question 3

co-dominance

Answer 3

both alleles are completely expressed

Question 4

expressivity

Answer 4

the degree to which individuals with a particular genotype demonstrate that genotype.

Question 5

penetrance

Answer 5

the number of individuals who have a particular genotype demonstrating that genotype.

Question 6

epistasis

Answer 6

many genes influences one characteristic

Question 7

pleiotropy

Answer 7

one gene influences many characteristics

Question 8

Expressivity and penetrance are influenced by

Answer 8

epigenetic factors

Question 9

epigenetic factors

Answer 9

factors other than the immediate genes that regulates the expression of these genes; often enviromental factors

Question 10

external environmental factors

Answer 10

temperature on the sexual phenotype of turtles

Question 11

internal environmental factors

Answer 11

modifiers, enhancers, or silencers

Question 12

lethality is expressed in what state?

Answer 12

homozygote state, either dominant or recessive

Question 13

how to calculate number of possible genotypes

Answer 13

[n(n+1)]/2 ex. 2 alleles = [2(2+1)]/2 = 3

Question 14

in co-dominance, both alleles are

Answer 14

completely expressed

Question 15

alleles for blood type A

Answer 15

iA, i

Question 16

alleles for blood type B

Answer 16

iB, i

Question 17

alleles for blood type AB

Answer 17

iA, iB

Question 18

alleles for blood type O

Answer 18

ii

Question 19

example of epistasis

Answer 19

labradors pigment, laying it down

Question 20

test for epistasis

Answer 20

complementation test; determines if a phenotype is due to a mutation at one location or if multiple locations are involved

Question 21

cytoplasmic (maternal) inheritance

Answer 21

due to the mitochondria or chloroplast being present in the egg; organism will have the same mitochonrial genes as mother, maternal grandmother, but differ from father

Question 22

characteristics of cytoplasmically inherited traits

Answer 22

present in males and females; typically inherited from just the mother; reciprocal crosses give different results; exhibit extensive phenotypic variation even within af single family

Question 23

maternal effect

Answer 23

prior to fertilization, the egg actively transcribed and translated info from a diploid cell and undergoes meiosis with this information; end result is that the offspring develops based on genotype of its mother

Question 24

imprinting

Answer 24

the environment (egg or sperm) wil linfluence the expression of a given gene

Question 25

sex-linked characteristic

Answer 25

genes located on the sex chromosome

Question 26

sex-influenced characteristic

Answer 26

genes on autosomal chromosomes that are more readily expressed in one sex

Question 27

sex-limited characteristic

Answer 27

autosomal genes whose expression is limited to one sex

Question 28

genetic maternal effect

Answer 28

nuclear genotype of the maternal parent

Question 29

cytoplasmic inheritance

Answer 29

cytoplasmic genes, which are usually inherited from only one parent

Question 30

genomic imprinting

Answer 30

genes whose expression is affected by the sex of the transmitting parent

Question 31

temperature sensitive mutations

Answer 31

permissive and non-permissive temperatures cause differences in speed of enzyme folding, too fast and it is non-functional