please explain step by step Albinism in humans is controlled by a recessive gene
ID: 18550 • Letter: P
Question
please explain step by stepAlbinism in humans is controlled by a recessive gene (a). from a marriage between two normally pigmented carriers (Aa) four children are produced. What is the probability
1.that their first child will be albino
2. that their first child will have normal pigmentation
3. of having 4 normally pigmented children
4.of having 2 normal and 2 affected children
5.of having at least one affected
Explanation / Answer
1- since they got an albino child, the man must be heterozygous Nn, and the woman is albino so shes nn the cross results in Nn, Nn, nn, nn, if one albino so the rest are albino, normal, normal... 2- 50% probability whatever children they got 3- I'm sorry I can't really explain it; it's tough on the net but I think the answer is male: Rr, female A: RR, female B: Rr since the offspring ratio is approximately 3:2 ---> we don't use the term "punnet square" in my country so I don't know what you mean... 4- heterozygous black means Bb, B dominant is black allele and b is recessive so it's the allele for brown colour. That means the parents are Bb and bb, its 2 black: 2 brown which is the same as 1 black : 1 brown offspring. ---> 50% ---> 0.5^4 = 0.0625 ---> 6.25% 5- If both parents are short haired, and produce short haired guinea pigs with a few guinea pigs, then the ratio of offspring is probably 3:2 as in number 3 (like in 7rose combed: 2single combed).. And if the ratio is 3:2 the parents must be heterozygous... The dominant allele shows its effect on the phenotype -short hair-. Thus the recessive allele is long hair.
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