Question

(a) Why did T.H. Morgan select Drosophila melanogaster as a specimen for his experiments?
(b) Morgan, in his dihybrid crosses with Drosophila observed deviations in the phenotypic ratio of F2 progeny in comparison to that of Mendel. With the help of a suitable example, explain how his results deviated from that of Mendel.

Answer 1

Answer:

a. because, it has very short life span

quickly breedable, male and female are easily distinguished, per mating produce number of procedure,

Answer 2

T.H. Morgan

Explanation:

• T.H. Morgan choose Drosophila Melanogaster for his experiments because
• It is easily available  on Banana or Mango fruits.
• Inside the bottles flies can be reared.

• A single mating can produce numerous individual within 2 weeks.
• Morgan studied genes that were sex linked in Drosophila Melanogaster dihybrid cross.
• Morgan crossed yellow bodied, white eyed females with brown bodied red eyed males.
• Morgan then intercrossed their F1 Progeny.
• Morgan found  that the two genes did not segregate independently of each other.

• He concluded with reference to Mendel's law that the F2 generation is different from the 9:3:3:1 ratio.
• Morgan's results are deviated from that of Mendel due to the phenomena of linkage and recombination.
• The genes which are tightly linked on the same chromosomes showed very less recombination. The genes which are loosely linked on the same chromosomes showed higher recombination.