EVOLUTION
HARDY WEINBERG EQUILIBRIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Half heterozygous, half homozygous dominant
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Half round, half wrinkled
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All heterozygous
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All round
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Detailed explanation-1: -The homozygous dominant variety will make all gametes with “R” allele only. Random fertilization of gametes of two parent plants will obtain RR (homozygous dominant) and Rr (heterozygous dominant) genotypes in 1:1 ratio.
Detailed explanation-2: -The expected genotype ratio when two heterozygotes are crossed is 1 (homozygous dominant) : 2 (heterozygous) : 1 (homozygous recessive). When a phenotypic ratio of 2 : 1 is observed, there is probably a lethal allele.
Detailed explanation-3: -You’ll note that 100% of all offspring are Rr, which is the genotype. Since the genotype for all offspring are the same, and the Rr genotype encodes a pink color, then 100% of the phenotypes will be pink (NOT red-remember that this is incomplete dominance).
Detailed explanation-4: -A true-breeding plant with round seeds would have a genotype of (RR) for that trait and a true-breeding plant with wrinkled seeds would have a genotype of (rr).
Detailed explanation-5: -For each trait, we expect 3/4 of the progeny to show the dominant phenotype. Therefore, the probability of the progeny showing all three dominant phenotypes = (3/4)(3/4)(3/4) = 27/64.