GENETICS AND EVOLUTION
GENETIC BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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BB and Bb
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Bb and bb
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BB only
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Bb only
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Detailed explanation-1: -Both of the individuals have B and b alleles as their gametes and thus all the genotypes are possible from it. There can be organisms with genotypes BB, Bb and bb which are possible from the gametes of the heterozygous organisms.
Detailed explanation-2: -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-3: -If two heterozygotes are crossed, the probability that an offspring will be homozygous recessive is 25% or 0.25. Homozygous dominant: 25% or 0.25.
Detailed explanation-4: -In another example (shown below), if the parent plants both have heterozygous (YG) genotypes, there will be 25% YY, 50% YG, and 25% GG offspring on average. These percentages are determined based on the fact that each of the 4 offspring boxes in a Punnett square is 25% (1 out of 4).