In cats, the Dense pigment gene, D/d, codes for melanophilin, a protein involved in the transportation and deposition of pigment into a growing hair. A separate gene, M/m, is responsible for the production of the pigment, with M_ producing black pigment and mm producing brown. When a cat has two recessive d alleles, its fur is a light gray color regardless of which alleles of M/m are present. Required:
State the phenotype and frequency for each of the following outcomes of a dihybrid cross:

a. M_D_
b. M__dd
c. mmD
d. mmdd

a. M_D_ : 9/16 Black furred individuals

b. M__dd : 3/16 gray furred individuals (1/16 MMdd + 2/16 Mmdd)

c. mmD_ : 3/16 Brow-furred individuals (1/16 mmDD + 2/16 mmDd)

d. mmdd: 1/16 gray furred individuals.

Explanation:

Available data:

Cross: between two dihybrids

Parental)         DdMm     x     DdMm

Phenotype) Black-furred      Black-furred

Gametes) DM, Dm, dM, dm   DM, Dm, dM, dm

Punnet Square)    DM        Dm         dM          dm

             DM       DDMM    DDMm   DdMM   DdMm

             Dm       DDMm    DDmm   DdMm   Ddmm

             dM        DdMM    DdMm    ddMM   ddMm

             dm        DdMm    Ddmm    ddMm   ddmm

F1) 9/16 Black-furred individuals, D-M- (1/16 DDMM + 2/16 DDMm + 2/16    

                                                                 DdMM + 4/16 DdMm)

    3/16 Brown-furred individuals, D-mm ( 1/16 DDmm + 2/16 Ddmm)

    4/16 Gray-furred individuals, dd-- ( 1/16ddMM + 1/16 ddmm + 2/16 ddMm)

ucd e e. rr. t t t t t t. to

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.