2.On the planet LongLiveRock, there is a recessive condition known as WhoAreYou.
ID: 73080 • Letter: 2
Question
2.On the planet LongLiveRock, there is a recessive condition known as WhoAreYou. People with this trait have an uncontrollable perform windmill guitar swings. The two alleles at the trait locus are labeled R (trait) and r (wild type). If the probability of transmitting an R allele is 0.76, then what is the probability that any child born to carrier parents will be affected (i.e., will perform windmill guitar swings)?
A. 0.76 B. 0.58 C. 0.62 D. 0.42 E. 0.24
3.Among Urepian Rock-things, skin texture is determined by a single autosomal gene. The wild type allele of this gene (th+) codes for hard, scale-like skin, whereas a mutant allele (th) codes for soft, smooth skin. When a Rock-thing with hard skin is crossed with a Rock-thing whose phenotype is soft, smooth skin, only smooth, soft-skinned offspring are ever observed. One possible answer is that: (Hint: For each answer, see if the offspring phenotypes are consistent the parental matings).
A. the parental Rock-thing with the soft, smooth skin is homozygous at the gene and the th allele is dominant.
B. the parental Rock-thing with the hard skin is heterozygous for the gene and the th+ allele is dominant.
C. the parental Rock-thing with the hard skin is homozygous at the gene and the th+ allele is dominant.
D. the parental Rock-thing with the soft, smooth skin is heterozygous at the gene and the th+ allele is dominant.
E. neither allele is dominant
Explanation / Answer
(2) Answer is B.0.58
The only offspring who receive both the recessive alleles "rr" will be affected by the trait.
To get affected, they need to receive alleles "rr"
Probability of transmitting an R allele is 0.76
Probability of transmitting r allele is 1-0.76=0.24
The probability of any child born to carrier parents will be affected is 0.24 x 0.24= 0.0576 or 58
Rr x Rr
25% RR 25% Rr 25%rr
(3) Answer is
A. the parental Rock-thing with the soft, smooth skin is homozygous at the gene and the th allele is dominant.
As mentioned, Rock-thing with hard skin (thth) x crossed with a Rock-thing with soft, smooth skin (th+th+ )
Then all the offspring will have the genotype thth+, with a phenotype of smooth, soft-skinned
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