1. watermelons bitter fruit (B) is dominate to sweet fruit (b) and yellow spots

Question

1. watermelons bitter fruit (B) is dominate to sweet fruit (b) and yellow spots (S) are dominate to no spots (s). A homozygous plant that has bitter fruit and no spots is crossed with a homozygous plant that has Sweet fruit and yellow spots. if the F1 are intercrossed to produce F2.

a.what will the phenotypic ratios in F2?

b. if F1 plant is back crossed with the bitter, unspotted parent, what phenotypes and proportions are expected in the offspring?

c. if F1 is back crossed with sweet, yellow spotted parent, what phenotypes and proportions are expected in the offspring?

2.is white or black fur coat in cats a recessive trait?

biter fivit is detenisane over sweet frui (MM ernd yellow spots no spris (s). The aenos these we independently, honourgou that has Momozymus plan meet and crossed with a Tallow pots. The Flate (a) What wil the phenotypic ratioi (b) If an Fr plan backcrossed with de bi ter, unspotted parent, wlal phenotypos and Proportia are expected he onspring? (e) If an Fi Panc is backcrossed with the wwdet, yellow spound parent, what and proportions are in the offspring? 2. Joe has a while cat named Sam. When Joe crosses Sam with a blak cat, he obtains while ens and black kittens. When the black kitens are interbred, they prod all black color in on the basis of these would you uee coat cats is a conclude tha white or black recessive trait? Explain your reasoning,

Explanation / Answer

Answers:

1. (a) P: BBss x bbSS

F1: BbSs

F2: 1/4BB1/4SS= 1/16BBSS (bitter, spots)

1/2Ss= 1/8BBSs (bitter, spots)

1/4ss= 1/16BBss (bitter, no spots)

1/2Bb 1/4SS= 1/8BbSS (bitter, spots)

1/2Ss= 1/4BbSs (bitter, spots)

1/4ss= 1/8Bbss (bitter, no spots)

1/4bb 1/4SS= 1/16bbSS (sweet, spots)

1/2Ss= 1/8bbSs (sweet, spots)

1/4ss= 1/16bbss (sweet, no spots)

Phenotypes: Bitter, spots = 9/16

Bitter, no spots = 3/16

Sweet, spots = 3/16

Sweet, no spots = 1/16

Ratio: 9:3:3:1

(b) Cross: BbSs x BBss

Progeny:BBSs, BBss, BbSs, Bbss (Bitter, yellow spots : Bitter, no spots = 1 : 1)

(c) Cross: BbSs x bbSS

Progeny: 1/4 BbSS (Bitter, yellow spots); 1/4 BbSs (Bitter, yellow spots), 1/4 bbSS (Sweet, yellow spots), 1/4 bbSs(Sweet, yellow spots)

2. The black coat color is likely recessive.

When Sam was crossed with a black cat,one-half of the offspring were white and one-half were black. This ratio potentially indicates that one of the parental cats is heterozygous dominant while the other parental cat is homozygous recessive—a testcross. The interbreeding of the black kittens produced only black kittens, indicating that the black kittens are likely to be homozygous, and thus the black coat color is the recessive trait.

If the black allele was dominant, we would have expectedthe black kittens to beheterozygous, containing a black coat color allele and a white coat color allele. Under this condition, we would expect one-fourth of the progeny from the interbred black kittens to have white coats. Because this did not happen, we can conclude that the black coat color is recessive

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