Chapter three, test one

Question 1

who coined the terms genetics, allele, homozygote, and heterozygote

Answer 1

bateson

Question 2

what is incomplete dominance

Answer 2

the relationship between two alleles of a gene where the heterozygote has a phenotype intermediate between that of the two homozygotes
does not resemble either pure bred parent

Question 3

where do you see not complete dominance

Answer 3

in F1

Question 4

if F1 of incomplete dominance self fertilize, what is the F2 phenotypic ratio

Answer 4

1:2:1

Question 5

if F1 of incomplete dominance self fertilize, what is the F2 genotypic ratio

Answer 5

1:2:1

Question 6

describe F2 ratio of incomplete dominance

Answer 6

1: parent
2: recombinant
1: parent

Question 7

what is the biochemical explanation of incomplete dominance

Answer 7

each allele of the gene under analysis specifies an alternative form of a protein molecule with an enzymatic role in a certain production
homozygous recessive has nonfunctional enzyme
heterozygote has semifunctional enzyme that can produce a new phenotype

Question 8

what does codominant mean

Answer 8

describes the relationship between two alleles of a gene where the heterozygote has the traits of both homozygotes

Question 9

what are the phenotype ratios for the f2 generation of codominance

Answer 9

1:2:1

Question 10

what are the genotype ratios for the F2 generation of codominance

Answer 10

1 homo dom: 2 both parents: 1 homo recess

Question 11

what is an example of codominance

Answer 11

blood type

Question 12

determinance of dominance relationships depends on what

Answer 12

the phenotype that appears in the F1 generation

Question 13

what do the F1 generation look like for complete dominance

Answer 13

one of the true breeding parents

Question 14

what do the F1 generation look like for incomplete dominance

Answer 14

resemble neither of parents

Question 15

what do the F1 generation look like for codominance

Answer 15

both pure bred parents show

Question 16

does codominance or incomplete affect law of segregation

Answer 16

no because it is based on proteins and enzymes present whether allele shows up in a certain way

Question 17

is it possible to have more than two alleles

Answer 17

yes ex: blood type

but one person can only carry two alternatives

Question 18

what examples shows that allele is codominant with every allele making a unique phenotype

Answer 18

histocompatibility antigens

Question 19

how do multiple alleles on an allelic series arise

Answer 19

mutations

Question 20

in what cells do mutations pass on

Answer 20

gamete producing cells

Question 21

how can you calculate the number of genes based on people present

Answer 21

two genes per person

2 x # people

Question 22

what is an allele frequency

Answer 22

the proportion of all copies of a gene in a population that are of a given allele type

Question 23

what are wild type alleles

Answer 23

the most common alleles in a population

Question 24

what makes an allele a wildtype

Answer 24

occurs in population at a frequency greater than 1%

Question 25

what is monomorphic

Answer 25

a gene with only one wild type allele

Question 26

what is polymorphic

Answer 26

more than one common allele

Question 27

what is a common variant

Answer 27

high frequency alleles of a polymorphic gene

Question 28

what is an example of a polymorphic gene

Answer 28

Histocompatibility antigens

Question 29

what is pleiotropy

Answer 29

phenomenon in which a single gene determines a number of distinct and seemingly unrelated characteristics

Question 30

what is a recessive lethal allele

Answer 30

an allele that prevent the birth or survival of homozygotes, though heterozygotes carrying the allele survive in utero

Question 31

how can lethal recessive or delayed lethality be passed on

Answer 31

from heterozygote carriers

Question 32

how can delayed lethality be passed on

Answer 32

heterozygote carriers | or homozygote that live past puberty

Question 33

dominant early lethal mutant alleles must be new

Answer 33

mutations because allele cant be passed on

Question 34

how do you determine 2 genes affecting one trait

Answer 34

self fertilize F2

Question 35

what shows that 2 genes affect one trait

Answer 35

presence or absence of dominant alleles of two genes | determines pheno and genotype

Question 36

can the F2 genotypes be grouped in a 2 gene determine one trait if it is incomplete or codominance occur

Answer 36

no | give rise to more than four phenotypes

Question 37

what biochemical pathway tells us about 2 gene affecting one trait

Answer 37

function additively in independent biochemical pathways

Question 38

what is epistasis

Answer 38

a gene interaction in which the effects of alleles at one gene hide the effects of alleles at another gene

Question 39

what is recessive epistasis

Answer 39

a gene interaction with which the effects of recessive alleles at one gene hide the effects of alleles at another gene

Question 40

what is the ratio for the F2 generation in a recessive epistasis

Answer 40

``` 9:3:4 4 represents (3+1) because ee masks the second gene ```

Question 41

what is reciprocal recessive epistasis

Answer 41

an interaction between alleles of two different genes where the homozygous recessive genotype of each gene prevents the phenotypic expression of the dominant allele of the other gene

Question 42

what is the ratio of the F2 generation for reciprocal recessive epistasis

Answer 42

9:7

Question 43

what is dominant epistasis

Answer 43

a phenomenon where the effects of a dominant allele of one gene hide the effects of alleles at another gene

Question 44

what is the F2 generation ratio for dominant epistasis

Answer 44

12: 3:1 13: 3

Question 45

what are some important factors of epistasis

Answer 45

interaction between alleles of different genes | F2 pheno ratios depend on functions of specific alleles and their biochemical pathways

Question 46

what does recessive epistasis reveal

Answer 46

dominant alleles of two genes function in same pathways to achieve a common outcome

Question 47

what does dominant epistasis reveal

Answer 47

indicates dominant alleles of two genes have antagonistic functions

Question 48

what is redundant gene action

Answer 48

a phenomenon where dominant, functional alleles of either or the other of two genes is required in the pathway

Question 49

what is the F2 phenotypic ration showing redundancy

Answer 49

15:1

Question 50

what is a heterogenous trait

Answer 50

a phenotype caused by a mutation in any one of a number of different genes

Question 51

what is locus heterogeneity

Answer 51

describes a trait where mutations in any one of two or more genes results in the same mutant phenotype

Question 52

what is a complementation test

Answer 52

method of discovering whether two mutations are in the same or separate genes

Question 53

what is complementation

Answer 53

the process in which heterozygosity for loss of function mutant recessive alleles for two different genes produces a normal phenotype

Question 54

what are multifactorial traits

Answer 54

traits determined be several factors, including multiple genes interacting with each other and one or more genes interacting with the environment

Question 55

what factors can alter the phenotypic expression of a genotype

Answer 55

modifier genes environment chance

Question 56

what is penetrance

Answer 56

in a population, the fraction of individuals with a particular genotype that show the associated phenotype

Question 57

what is expressivity

Answer 57

the degree of intensity with which a particular genotype is expressed as a phenotype

Question 58

what are modifier genes

Answer 58

genes that produce a subtle, secondary effect on phenotype

Question 59

what is a phenocopy

Answer 59

a change in phenotype arising from environmental agents that mimics the effects of a mutation in a gene

Question 60

are phenocopies heritable

Answer 60

no bc they do not result from a change in a gene