1 In rabbits, black coat color is due to a dominant gene B, brown coat color is due to a recessive gene b. Short hair is due to a dominant gene S, long hair to its recessive allele s. In a cross between 2 heterozygous black, short haired rabbits, what would be the phenotypic ratio of the offspring? Page 88, Dihybrid Problems #2

2 SbBSs B – black coatb – brown coat S – short hairs – long hair Cross between 2 heterozygous black, short haired rabbits BbSs x BbSs Bbs BS Bs bS bs

3 bsbS BsBS bs bS Bs BBSSBBSsBbSS BbSs BBSs BBss BbSs Bbss BbSS BbSs bbSS bbSs BbSs Bbss bbSs bbss #1 Results

4 bsbSBsBS bs bS Bs BBSSBBSsBbSS BbSs BBSs BbSS BbSs BBssBbSsBbss BbSsbbSSbbSs Bbssbbss bbSs B – black; b – brown; S – short; s - long Black (B), short (S) Black (B), long (s) Brown (b), short (S) Brown (b), long (s) 9 : 3 : 3 : 1

5 In horses, black color is dependent upon a dominant gene B, and chestnut upon its recessive allele b. The trotting gait is due to a dominant gene T and the pacing gait to its recessive allele t. if a homozygous black pacer is mated to a homozygous chestnut trotter, what will the genotype and phenotype of the F 1 generation be? Page 88, Dihybrid Problems #2

6 B – black b – chestnut T - trottingt – pacing HomozygousxHomozygous black pacer chestnut trotter BBtt x bbTT bT bT Bt Bt

7 Bt bT B – black; b – chestnut; T – trotting; t - pacing BbTt BbTt All offspring BbTt — Black Trotters

8 If two F 1 individuals from #3 were mated, what would be the phenotypic ratio of the offspring? BbTt x BbTt BT Bt bT bt Page 88, Dihybrid Problems #3

9 BT Bt bT bt BT Bt bT bt B – black; b – chestnut; T – trotting; t - pacing BBTT BBTt BbTT BbTt BBTt BBtt BbTt Bbtt BbTT BbTt bbTT bbTt BbTt Bbtt bbTt bbtt 9:3:3:1

10 An organisms has the genotype AABb. It is crossed with an individual with the genotype Aabb. What type of gametes can be produced by these two individuals? AABb x Aabb AB Ab AB Ab Ab Ab ab ab Page 88, Dihybrid Problems #4