GENE ACTION Flashcards
What does gene action do ?
effects the genotype of a particular trait affects the expression in phenotype
what are the different types of gene action
non- additive
.sex-linked
.Sex-limited
.Sex-influenced
.additive -
what is sex influenced ?
trait the gender affects the way it is being expressed
what is additive
influence of one gene to another gene
Sex linked gene found on x and Y chromosomes
All other genes are autosomal
what is non additive gene action
.qualitative traits -> few genes
Qualitative traits
- One or few genes ex. Coat color , horn/polled , disease
- They are not affected by the environment
- They can other be classified into categories
what is complete dominance ?
- One allele of a pair can mask the expression of the other (recessive )
- Recessive expression = homozygous condition
what are some examples of complete dominance
Coat color in Hereford and Angus cattle
- Angus= black
- Hereford =red
.black is dominant to red
how would Homozygous dominant be written?
BB
How would heterozygous be written ?
Bb
how would heterozygous recessive be written?
bb
what is incomplete dominance ?
. Heterozygote -> different phenotype
genotype is what ?
the gene
ex. RR.Rr,rr
phenotype is what ?
appearance
ex. coat color, red, roan , white
what is he genotypic ratio ?
1RR :2Rr :1rr
what is the phenotypic ratio ?
1 red :2 roan : 1 white
what is epistasis ?
non- allelic interaction (phenotypic effect depends on what alleles are present )
what is and ex of Complete dominance epistasis
- Wool pigment in sheep
understand episatsis
BBww x bbWW
(black male x white female)
do chart
sex linkage
sex determined by inheritance of entire chromosome
x chromosome =
relationship with inheritance of sex
y chromosome =
very few loci identified as controlling traits unrelated to sex of the individual
true or false : x chromosome carries genes for many traits
true
sex linkage concerned with what ?
inheritance of traits controlled by alleles on x chromosome
ex. color in cats
