Biology · Variation and Genetics
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In a mating between two individuals those are heterozygous for a recessive lethal allele.What genotypic ratio (homozygous dominant : heterozygous : homozygous recessive) would you expect to observe in the offspring?
- A
1:2:1
- B
3:1:1
- C
1:2:0
- D
0:2:1
Explanation is given below
a) 1:2:1
This option suggests that the expected genotypic ratio of the offspring from the mating of two heterozygous individuals for a recessive lethal allele would be 1 homozygous dominant: 2 heterozygous: 1 homozygous recessive. This is the classic Mendelian genotypic ratio that results from a monohybrid cross between heterozygous individuals.
b) 3:1:1
This option suggests a genotypic ratio of 3 homozygous dominant: 1 heterozygous: 1 homozygous recessive in the offspring. This ratio does not match the expected genotypic ratio for a monohybrid cross involving heterozygous individuals.
c) 1:2:0
This option suggests a genotypic ratio of 1 homozygous dominant: 2 heterozygous: 0 homozygous recessive. This implies that no homozygous recessive offspring will be produced, which is unlikely in a monohybrid cross involving heterozygous individuals.
d) 0:2:1
This option suggests a genotypic ratio of 0 homozygous dominant: 2 heterozygous: 1 homozygous recessive. This means there would be no homozygous dominant offspring, which is not expected in a monohybrid cross.
Tagged under Biology · Variation and Genetics · 2017