NEET2005ZoologyPrinciples of Inheritance and VariationActual
Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F ₂ generation what proportion of the progeny is likely to resemble either parent?
Options
- ANone
- BLess than 5 percent
- COne third
- DHalf
Correct answer
B. Less than 5 percent
Step-by-step solution
Polygene results in quantitative inheritance. Quantitative inheritance is characterised by occurrence of intermediate forms between the parental type. There will be 7(1: 6: 15: 20: 15: 6: 1) phenotypes when three polygene pairs are involved. The total number of progeny would be 64 . Out of these sixty four only two will be likely to resemble either parents. Hence their proportion in F ₂ generation would be 3.12 i.e. less than five per cent.