PART 1B (8 pts) B. You find that the mutations that cause 1 km/h and 2 km/h spee
ID: 214137 • Letter: P
Question
PART 1B (8 pts) B. You find that the mutations that cause 1 km/h and 2 km/h speeds are ind A and gene B, respectively). These mutations are in genes separate genes (gene encoding proteins that produce speed-related hormones You heterozygotes bearing these mutations which you indicate as: create double A, B WT alleles in gene A and B a allele for 1 km/h speed b-allele for 2 km/h speed Aa Bb You mate these double heterozygotes together to perform a dihybrid cross What are the expected phenotype ratios of the progeny if a. The pathway below is correct? Explain your answer (4 pts) slowness hormone b. The pathway below is correct? Explain your answer (4 pts) slowness hormone 1 slowness hormone 2Explanation / Answer
b) in case 2 where both A and B gene are separatly inherited and are independent from each other. Mutation in A gene produce slowness hormone 1 and in B gene produce slowness hormone 2 . So phenotypic ratio of this particular pathway is 9:3:3:1.
When we cross Aa1Bb1 x Aa1Bb1
Gives AB, a1B, a1b2 , Ab2 gametes
AB. a1B. a1b2. Ab2
AB. AABB. Aa1BB. Aa1Bb2. AABb2
a1B. Aa1BB. a1a1BB. a1a1Bb2. Aa1Bb2
a1b2. Aa1Bb2. a1a1Bb2. a1a1b2b2. Aa1b2b2
Ab2. AABb2. Aa1Bb2. Aa1b2b2. AAb2b2
Here 9 = wild type
3 = wild type and slowness hormone 1
3= wild type and slowness hormone 2
1 = mutant type
9:3:3:1 dihybrid ratio is produced, because the mutation are in two parallel biochemical patways.
a) The progeny of dihybrid cross may produce just two phenotypic classes, in an 9:7 ratio. Loss of function of either A or B gene function has the same phenotype as loss of function of both gene due to complementry gene action. The function of both gene work together to form final product . Two gene when act together in one biochemical pathway the modified phenotylic rato will be 9:7 . 9 wild type and 7 have mutant type means slowness hormone. Presence of mutant allele of any 2 gene produce mutant phenotype.
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