Could someone help me with 6,7 and 8? i just dont understand so could you show t

Question

Could someone help me with 6,7 and 8? i just dont understand so could you show the work if its not too much?

6. In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man marries a blue-eyed woman and they have three children, two of which are brown-cyed and one of whom is blus- eyed, a. Draw the Punnett square that illustrates this marriage. b. What is the man's genotype? c. What are the genotypes of the children? 7. In sillworms a single gene determines the color of the cocoon, The yellow cocoon allele is What are the genotypic and phenotypic ratios of a cross between a dominant te the white allele. homezygous dominant male and a hetererygous female? hamesygous dominant male and s hetarezygus tenala? The yellow cocoon allele will be represented by& The white allele will be represented by The genotypie and phenotypic ratios of this cross are 8. In mice a single gene determines the color of the eyes. The black eyes allele is deminant to the red allele. What are the genotypic and phanotypic ratios of a eross between a heterezygous male and a heterozygous female? (Show all your work!)

Explanation / Answer

6. Brown allele B

Blue allele b

B is dominant over b therefore b is recessive and has to be in homozygous condition to express i.e. bb. Thus the woman who has blue eyes, has the genotype bb

the father can either homozygous dominant or heterozygous dominant. if the father would homozygous dominant i.e. BB, then all the children would be brown eyed but since one of the children is blue eyed, the father would be heterozygous i.e. Bb

The punnett square'

Man: Bb (Brown eyes)

Woman: bb (blue eyes)

B. b

b Bb bb

b Bb bb

The genotype of the brown eyed children is Bb whereas the blue eyed child's genotype is bb.

7. Yellow cacoon is dominant over white. Let YY be yellow cacoon and yy be the genotype for white cacoon.

Homozygous dominant male: YY.

Heterozygous female: Yy

Y Y

Y YY YY

y Yy Yy

The genotypic ratio is 1:1 (2 YY:2Yy)

the phenotypic ratio is 1 as all will be yellow colored cacoon.  

8. Black is dominant over red eyes.

Allele for black eyes: B

Allele for red eyes: b

Heterozygous male: Bb

Heterozygous females: Bb

B b

B BB Bb

b Bb bb

Genotypic ratio 1:2:1 (BB:Bb:Bb)

Phenotypic ratio 3:1 (black eyes: red eyes)

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