Lec 8 - Transmission Genetics

Genotype

exact genetic makeup

Phenotype

observable trait/characteristic

mode of inheritance

how the disease/trait is transmitted to next generation

2 parts to the Mendel’s laws

law of segregation and law of independent assortment

Law of segregation

alleles pairs separate/segregate during gamete formation and randomly unite at fertilization

law of independent assortment

during gamete formation, segregation of alleles of one allelic pair is independent of the alleles of another allelic pair (different chromosomes)

autosomal dominant

carries one mutant allele, the disease/trait is displayed. can’t tell the difference b/w the carrying of one or two mutant allele

autosomal dominant does not skip _____ and has no ____ bias

generations, sex/ratio

semi dominant/co-dominant/additive

one copy of mutations is enough to see phenotype, 2 copies shows more severely

recessive inheritance

two mutant alleles are necessary to see trait/disease

T/F? For recessive inheritance, carrier with one copy is still normal.

True

Recessive inheritance ______ generations and there ____ sex/ration bias

may skip, is no

X-linked

located on X chromosomes

T/F? For X-linked, males are affected.

True

Loss of function mutation

reduced/complete lose of protein function

T/F? Mutations that are recessive are likely to be loss of function

True

What is the most common type of mutation seen in domestic animals?

loss of function

Gain of function confers _____ activity

new/enhanced

T/F? Gain of function mutations are usually dominantly inherited

Complex mode of inheritance

not a 1:1 relationship b/w genetic variant and phenotype

________ locus is type of complex mode of inheritance mutation

risk/susceptibility

Risk/susceptibility locus is when the variant _____ risk of disease and it is usually _____ (multiple genes involved)

increases, polygenic

Incomplete penetrance

has copies of the mutation required to be affected w/ the disease but it is unaffected

Animals with incomplete penetrance breed as if it were affected or unaffected?

affected

Variable expressivity

same mutation manifests trait/disease to different degrees

Epistasis

one gene masks effect of other

dominant epistasis

1 dominant allele at one genes masks both dominant/recessive alleles at other gene

X inactivation

dosage compensation for extra ‘X’ found in females