Ans 215- Review For Test 2

Front 1

in ___ dominance, the same phenotype results whether the dominant allele is heterozygous or homozygous.

Back 1

complete

Front 2

in __ dominance, the phenotype of the heterozygote is intermediate between those of 2 homozygotes

Back 2

incomplete

Front 3

in ____, the heterozygote exhibits the phenotypes of both homozygotes

Back 3

codominance

Front 4

in many cases, different genes interact to determine phenotypic characteristics. In _____, for example, modified mendelian ratios occur bc of gene interactions; the phenotypic expression of one gene depends on the genotype of another gene locus

Back 4

epistasis

Front 5

Alleles of certain genes may be fatal to the individual. The existence of such ___ ____ indicates that the product usually produced by the nonlethal allele is essential for the function of the organism

Back 5

lethal allele

Front 6

___= the frequency at which an allele manifests itself phenotypically within a population.

Back 6

penetrance

Front 7

___= the kind or degree of phenotypic manifestation of a gene or genotype in a particular individual

Back 7

expressivity

Front 8

what influences gene expression?

Back 8

organisms environment, both internal and external
internal- age and sex
external- nutrition, light, chemicals, temp, and infectious agents

Front 9

___= most of the genetic traits considered in the earlier discussion of the mendelian principles is determined predominantly by differences in genotype; that is, ____ differences result from genotypic differences

for many traits however, phenotype is influenced by genes and environment

Back 9

variation

Front 10

__= allele that causes death in early development

Back 10

lethal allele

Front 11

if you see a 2:1 ratio, it is almost always produced by a recessive ____ allele.

so allele cannot be transmitted to next generation unless allele is expressed after the onset of reproduction

Back 11

lethal

Front 12

examples of multiple alleles at at the same locus..

Back 12

ABO blood types
coat colors in rabbits

Front 13

in ___- 1 gene hides the effects of another gene at a diff locus

Back 13

epistasis

Front 14

____ =gene does the masking

__=gene that is masked

Back 14

epistatis


hypostatic

Front 15

reccessive epistasis examples...needs 'ee' to get this masking

Back 15

coat colors in labrador retreivers

Front 16

__ epistasis- only 1 copy of allele at one locus is needed to mask alleles at 2nd locus

Back 16

dominant

Front 17

how does epistasis occur?

Back 17

many cases of epistasis arised bc a gene that has an effect on a early step in a pathway will be epistatic to genes that affect subsequent steps, bc effect of enzyme in late steps depends on PRODUCT OF EARLIER REACTION

Front 18

__= 5 common alleles- determines depth and distribution of color

Back 18

agouti (A) locus

Front 19

___= 2 allelels, and determines if black pigment can be formed

Back 19

black (B) locus

Front 20

____= can full color be expressed; 5 alleles; full color to fully albino

Back 20

Albino (C) locus

Front 21

__= is color diluted; intense to diluted pigmentation

Back 21

dilution ( D) locus

Front 22

__= where is genotype for the A llocus expressed? Over entire body or restricted- 5 alleles

Back 22

extension (E) locus

Front 23

__= are white spots present; 4 allelesl range from no spots to almost white

Back 23

spotting (S) locus

Front 24

__= small colored spots on white areas; 2 alleles; either ticking or no ticking; cant be expressed if no spots at the S locus

Back 24

ticking (T) locus

Front 25

The ___ gene is responsible for eumelanin pigment

Back 25

B gene/ black

Front 26

The ___ gene restricts black pigment; mostly to the mane, tail, or legs (bay)

Back 26

the A gene

Front 27

The __ allele produces no dilution

cc thought to produce true albino

Back 27

C

Front 28

__ gene dilutes both black and red pigments; produces a dorsal stripe

Back 28

d gene

Front 29

___ gene produces a horse with white hairs mixed throughout the body, looks similar to gray, but has the white hairs at birth and doesnt change

Back 29

r gene (roan)

Front 30

the __gene, is a dominant gene that causes a silver dapple
makes a flaxen mane and tail

Back 30

the Z gene

Front 31

the __ gene is a dominant paint gene where white crosses the top line and all legs re white

Back 31

t (tobiano) gene

Front 32

the __ gene is a dominant gene that is a paint gene
if homozygous can cause lethal white bc of lethal defect of astresia coli

Back 32

O (overo) gene

Front 33

__ __ traits are determined by autosomal genes inherited according to mendels principles
-expressed differently in males and females
-examples; beards on goats- only one Bb allele needed to form beards on males, and 2 copies needed to form on females

Back 33

sex influenced

Front 34

extreme form of sex influenced trait is a __ ___ trait

Back 34

sex limited

Front 35

if ____ penetrance, the genotype may not express the expected phenotype

Back 35

incomplete penetrance

Front 36

__= percentage of individuals having a particular genotype that express the expected phenotype

Back 36

penetrance

Front 37

__= the degree to which a trait is expressed

Back 37

expressivity