Question

Blue flower is dominant to yellow flower. Tall plant is dominant to short. Cross BbTt * BbTt. What precenetage of the offsprings are expected to be heterozygous for both traits?

Answer 1

The correct answer would be - 25%.

Step-by-step explanation:

It is given that the Blue flower is dominant over the yellow flower which means Blue is represented by allele B here and allele b for yellow and Bb is a heterozygous case with a blue phenotypic character. Similarly, the Tall plant is dominant over short and represented by T and t respectively.

BbTt is a heterozygous condition and a cross with itself will produce :

Gametes: BT Bt bT and bt

BT Bt bT bt

BT BBTT BBTt BbTT BbTt

Bt BBTt BBtt BbTt Bbtt

bT BbTT BbTt bbTT bbTt

bt BbTt Bbtt bbTt bbtt

Here 4 out of 16 offspring are heterozygous for both traits represented by bold alphabets. Therefore the correct answer is 25%