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Question
Two heterozygous parents are crossed. If the two loci are linked, what would be the distribution of phenotypic features in the F1 generation for a dihybrid cross?
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Solution 1
Linkage is defined as the coexistence of two or more genes in the same chromosome. Linked genes are inherited together if they are on the same chromosome and close to each other.
For example, a cross between a yellow-bodied and white-eyed and wild-type parent in a Drosophila will produce wild-type and yellow-white progenies. It is because yellow-bodied and white-eyed genes are linked. Consequently, progenies inherit both traits simultaneously.
Solution 2
Two heterozygous parents (i.e. GgLl and GgLl) are crossed and the two loci are linked then the cross will be
This means, if ‘G’ represent grey body (dominant), ‘g’ black body (recessive), ‘L’-long (dominant) and ‘l’-dwarf (recessive) then the distribution of phenotypic features in F1 generation will be 3 : 1 i.e. 3/4 will show the dominant feature, grey and long, either in homozygous (GGLL) or in heterozygous (GgLl) condition and 1/4 will show the recessive feature, black and dwarf (ggll).
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Give Technical Term:
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