Answer:
Percentage of progeny that are albino are 50.00%
Percentage of progeny that are agouti are 37.50%
Percentage of progeny that are black are 12.5%
Explanation:
This question is a classic example of the genetic phenomena known as "epistasis", “Epistasis” is a word composed of Greek roots that mean “standing upon.” The alleles that are being masked or silenced are said to be hypostatic to the epistatic alleles that are doing the masking.
The agouti mouse (AA), is dominant over the black (aa). However, a separate gene (C) is necessary for pigment production. A mouse with a recessive 'c' allele at this locus is unable to produce pigment and is albino regardless of the allele present at locus A.
Hence, A cross between heterozygotes for both genes (AaCc x Aacc)
is show in the pdf below and would generate offspring with a phenotypic ratio of:
albino : 8/16 (i.e 50.00%)
agouti: 6/16 (i.e 37.50%)
black: 2/16 (i.e 12.5%)
This is so FOR albino, Since cc_ = albino independent of A/a gene genotype. Therefore, all traits carrying albino independent is 8/16. i.e ( AAcc, Aacc, AAcc, Aacc, Aacc, aacc, Aacc, aacc)
= 50.00%
FOR agouti: Since C_ = non-albino with A/a gene determining phenotype & A_ = Agouti if non-albino. Therefore, any progeny carrying heterozygous agouti (i.e A) and albino (i.e C) is Agouti.
Hence, agouti = (those that are all heterozygous (AACc, AaCc, AACc, AaCc, AaCc, AaCc) )
=6/16 (i.e 37.50%)
FOR Black: Since aa = black if non-albino & C_ ( non-albino with A/a gene determining phenotype ). Black will be homozygous recessive agouti and heterozygous albino (aaCc and aaCc).
=2/16
= 12.5%
I HOPE THIS REALLY HELPS A LOT!.
