NEET BIOLOGY

GENETICS AND EVOLUTION

EVOLUTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What does the genotype need to be of two dominant parents who produce a recessive child?
A
BB x BB
B
Bb x Bb
C
BB x bb
D
bb x bb
Explanation: 

Detailed explanation-1: -If the brown male had been BB, then all offspring would have been Bb and all brown. However, if the male is Bb as above and you perform a testcross, 50% of all offspring should have the bb genotype and a white phenotype.

Detailed explanation-2: -A dominant allele produces a dominant phenotype in individuals who have one copy of the allele, which can come from just one parent. For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent.

Detailed explanation-3: -Each parent contributes one allele to each of its offspring. Thus, in this cross, all offspring will have the Bb genotype. Each parent contributes one allele to each of its offspring. Thus, in this cross, all offspring will have the Bb genotype.

Detailed explanation-4: -When you have two copies of the alleles that are both dominant, this is called codominance . For example, if the dominant trait is red for flowers and another dominant trait is white, then the flower will have both red and white as the dominant traits are expressed equally.

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