WAEC - Biology (2012 - No. 57)
Two yellow-flowered hybrid plants each carrying a recessive factor for flowers with green colour were crossed.
Which of the following ratios shows the correct proportion of offspring that have green flowers?
Which of the following ratios shows the correct proportion of offspring that have green flowers?
2 in 2
1 in 3
1 in 4
1 in 5
Explication
When two yellow-flowered hybrid plants each carrying a recessive factor for green flowers are crossed, the genotype of the parents would be Yy (where Y represents the dominant yellow flower allele and y represents the recessive green flower allele). The possible genotypes of the offspring from this cross would be YY, Yy, Yy, and yy. Among these, only the yy genotype will result in green flowers.