Question

need help with all these question 1,2,3

Additional Genetics Problems Radishes may be along or round in shape. Cras been oval and round produced 18 round and 177 al crosses between land long eve 200 waland 20 lag Crowse between oud and long gave 545 cal. Crosses beren o ndoanells long. 240 oval, and 121 round. What type of inheritance is involved Incomplete dominance 2 summer squashes, white fruit (W) is dominant over colored fruit (w), and dish-shaped fruit (D) is dominant wer slabe cured fruit (d) How many different genotypes may squash plants have with regard to these two pairs of characteristics? S (3) One variety of tomato has fine hairs on its skin. When a typical smooth-skinned tomato was crossed with a hairy tomato, all of the offspring had smooth skin. Crosses between the F, smooth-skinned tomatoes, however, produced 221 hairy tomatoes and 656 smooth-skinned tomatoes. How are the skin types inherited? ESSS

Answer 1

( the first question marked 3 is not complete it is part of some other question, alleles are not defined so starting with first complete question)

1) there are three phenotypes oval. round and long

Long * round

all the offsprings are oval, this shows the long and round are homozygotes and the oval is a heterozygote, so this is an example of incomplete dominance, the heterozygotes show intermediate phenotype compared to homozygotes.

let the alleles be L-long, R-round

LL-long

LR- oval

RR- round

Oval * round

LR * RR

	L	R
R	LR ( oval)	RR ( round)

the expected phenotypic ratio is oval:round=1:1

the observed ratio is oval:round=177:181=1.022=1

oval * long

LR * LL

	L	R
L	LL (long)	LR (oval)

the expected phenotypic ratio is long:oval=1:1

the observed phenotypic ratio is long:oval=206:202=1.02:1

oval * oval

LR * LR

	L	R
L	LL (long)	LR (oval)
R	LR (oval)	RR ( round)

the expected phenotypic ratio is

long: oval:round=1:2:1

the observed phenotypic ratio is long: oval:round=118:240:121=1:2.04:1.025

the ratio is simplified by dividing with the smallest number

so the expected ratios are almost similar to the observed ratio so the mode of inheritance is incomplete dominance.

2) different possible genotypes are

WWDD, WWDd, WWdd, WwDD, Wwdd, WwDd, wwDD, wwDd, wwdd

3) let the alleles be S-smooth skin, s-hairy skin

smooth skinned * hairy skinned

all progenies are smooth-skinned, means the smooth-skinned is dominant to hairy-skinned

SS * ss

Ss

Ss * Ss

	S	s
S	SS (smooth-skinned)	Ss(smooth-skinned)
s	Ss(smooth-skinned)	ss ( hairy skinned)

expected phenotypic ratio is

smooth-skinned: hairy skinned=3:1

the observed phenotypic ratio is

smooth-skinned: hairy skinned= 656:221=2,9:1

the ratio is simplified by dividing with the smallest number

so the expected ratios are almost similar to the observed ratio so the mode of inheritance is smooth skin is dominant to hairy skin.