NEET BIOLOGY

GENETICS AND EVOLUTION

GENETIC BASIS OF INHERITANCE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A phenotype that results from a dominant allele must have at least ____ dominant allele(s) present in the parent(s)
A
1
B
2
C
3
D
4
Explanation: 

Detailed explanation-1: -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-2: -Individuals inherit two versions of each gene, known as alleles, from each parent. In the case of a dominant trait, only one copy of the dominant allele is required to express the trait.

Detailed explanation-3: -Dominant alleles show their effect even if the individual only has one copy of the allele (also known as being heterozygous?). For example, the allele for brown eyes is dominant, therefore you only need one copy of the ‘brown eye’ allele to have brown eyes (although, with two copies you will still have brown eyes).

Detailed explanation-4: -A dominant allele is denoted by a capital letter (A versus a). Since each parent provides one allele, the possible combinations are: AA, Aa, and aa. Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.

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