How did he disprove Mendelian dihybrid F2 phenotypic ratio explain giving reason?
Explanation: When Morgan conducted dihybrid cross on Drosophila like Mendel did with pea plants, the F2 ratios deviated significantly from than of Mendel’s F2 ratio During the studies on genes in Drosopila that were sex-linked T.H. Morgan found F2-populabon phenotypic ratios deviated from expected 9 : 3 : 3 : 1.
Why did the Morgan Select Drosophila melanogaster for his experiment how did he disprove Mendelian dihybrid F2 phenotypic ratio of 9 3 3 1 explain giving reasons?
b) Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F1 progeny. He observed that the two genes did not segregate independently of each other and the F2 ratio deviated very significantly from the 9:3:3:1 ratio (expected when the two genes are independent).
What could cause the ratio in a dihybrid cross to not be 9 3 3 1?
When two genes are involved in the outcome of one characteristic, a dihybrid cross involving these genes can produce a phenotypic ratio very different from 9:3:3:1.
Why does linkage and recombination bring a deviation in the Mendelian ratio of 9 3 3 1 for a dihybrid cross?
F ratio was observed to be significantly different from 9:3:3:1 as observed in Mendelian dihybrid cross. Explanation of deviation from Mendelian ratio: Genes involved are located on X chromosome. … Recombination − Non-parental gene combination.
Why was Morgan selected for his experiment?
Morgan selected fruit flies for his genetical experiments for the following reasons : (a) They could be grown on simple synthetic medium in the laboratory. (b) They complete their life cycle in about two weeks and a single mating could produce a large number of progeny flies.
Why did TH Morgan choose Drosophila?
T. H. Morgan selected Drosophila melanogaster to study sex-linked genes in his lab experiment due to the following reasons: … (ii) Sex-linked traits such as red eye colour and white eye colour are found only in Drosophila melanogaster, where white eye colour in males is a sex-linked recessive trait.
How did Alfred Sturtevant map genes on chromosome?
Higher recombination frequencies meant that the genes were farther apart on the chromosome. Conversely, the lower the frequency, the closer together on the chromosomes the genes likely were. By analyzing the recombination frequency data, Sturtevant found the distances between each gene.
What is linkage and recombination Class 12?
This concluded that genes are linked. This process is called linkage. Recombination is the rearrangement of genetic material. The generation of non-parental gene combination during dihybrid cross is called recombination. When genes are located on same chromosome, they are tightly linked and show less linkage.
What does a 3 1 ratio mean in genetics?
The F2 generation always produced a 3:1 ratio where the dominant trait is present three times as often as the recessive trait. Mendel coined two terms to describe the relationship of the two phenotypes based on the F1 and F2 phenotypes.