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During the studies on genes in Drosopila...

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. Explain the conclusion he arrived at.

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1. T. H . Morgan worked on fruit flies (Drosphila Melanogaster).
2. They are found suitable for studies in genetics for the following reasons :
- They could be grown on simple synthetic medium in the laboratory.
- The flies complete their life cycle in about two weeks.
3. Morgan carried our many dihybrid crosses in Drosophila, with the genes that were sex-lined, i.e., the genes are present on the X-chromosome.
4. He observed that the two genes under consideration in his experiments, did not segregate independently as in the case of characters studied by Mendel.
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T.H. morgan obtained phenytypic ration different from 9:3:3:1 during study on Drosophila. Explain its conclusion.

Morgan carried out several dihybrid crosses in Drosophila and found F_(2) -rations deviated very significantly from the expected Mendelian ratio. Explain his findings with the help of and example.

In a dihybrid cross carried by T.H. Morgan in Drosophila the F_(2) ratio deviated from that of Mendel's dihybrid F_(2) ratio. Give a reason.

Morgan hybridised yellow - bodied, white - eyed females to brown - bodued, red - eyed males and intercrossed their F_(1) progeny. He observed that (a) F_(2) ratio was deviated very significantly from the 9 : 3 : 3 : 1 ratio (b) Both genes did not segregate independently of each other (c) Recombinant types are not obtained in F_(2) generation (d) Both genes segergate in independently of each other . Select the correct set of statements :

Assertion : When yelow bodied, white eyed Drosophila females were hybridised with brown-bodied, red eyeed males , and F_(1) progeny was intercrossed, F_(2) ratio deviated from 9:3:3:1 Reason : When two genes in a dihybrid are on same chromosome, the proportion of parental gene combinations are much higher than the non-parental type

In a typical monohybrid cross the F_(2) -population ratio is written as 3:1 for phenotype but expressed as 1:2:1 for genotype. Explain with the help of an exmaple.

If the ratio of each phenotype of the seeds of pea plants in the F_(2) generation is 9 : 3 : 3 : 1, it is known as :

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