In a dihybrid cross white eyed, yellow bodied female Drosophila crossed with red eyed, brown bodied male Drosophila produced in F2 - generation 1.3% recombinants and 98.7% progeny with parental type combinations. This observation of Morgan deviated from Mendelian F2 - phenotypic dihybrid ratio. Explain, giving reasons Morgan’s observation.
Answers
Answer:
Due to higher proportion of linkage of parental genes, parental combinations are higher in F2 generation of Drosophila.
Explanation:
According to Mendel, for a Dihybrid cross, the F2 Phenotypic ratio is 9:3:3:1.
But, in the given scenario of dihybrid cross of white eyed, yellow bodied female Drosophila that is crossed with red eyed, brown bodied male Drosophila, Morgan observed some deviation in the ratio.
It produced 98.7% progeny with parental type combinations and 1.3% recombinants in F2 generation.
Morgan observed that when the two genes were located on same chromosome in a dihybrid cross, the parental gene combinations were much higher than non-parental ones.
He introduced the concept called 'Linkage', which is the physical association of genes on a chromosome.
When crossing over of genes occurs, the process is called 'Recombination'. Non-parental generation are called as 'Recombinants'.