In peas the gene for inflated pods (I) is dominant to its allele for constricted
ID: 69350 • Letter: I
Question
In peas the gene for inflated pods (I) is dominant to its allele for constricted pods (i). Letting S and s stand for smooth and wrinkled-seed alleles. Note: Smooth seeds are dominant to wrinkled seeds.
a. What is the probability that the first offspring of two plants each IiSs, will be a wrinkled-seed inflated pod plant?
b. What is the probability that the next offspring of these plants (IiSs x IiSs) will be a wrinkled-seed constricted pod plant?
I previously ask this same question, but was unfortunately unable to read the response (Pic of pen and paper too far away.)
Thank you!
Explanation / Answer
A cross between two IiSs plants leads to the formation of offspring with the following ratio.
Each plant would be able to produce the following gametes based on their genotype - IS, Is, iS, is
IISS
(Inflated, Smooth)
IISs
(Inflated, Smooth)
IiSS
(Inflated, Smooth)
IiSs
(Inflated, Smooth)
IISs
(Inflated, Smooth)
IIss
(Inflated, Wrinkled)
IiSs
(Inflated, Smooth)
Iiss
(Inflated, wrinkled)
IiSS
(Inflated, Smooth)
IiSs
(Inflated, Smooth)
iiSS
(Constricted, Smooth)
iiSs
(Constricted, Smooth)
IiSs
(Inflated, Smooth)
Iiss
(Inflated, wrinkled)
iiSs
(constricted, Smooth)
iiss
(Constricted, Wrinkled)
(a) Thus it could be ascertained that there is a probability of 3/16 of a chance that inflated, and wrinkled seed, if there is a cross between two plants with the genotype IiSs.
(b) The chance for getting a wrinkled-seed, constricted pod is around 1/16 times, if there is a cross between two plants with the genotype IiSs.
IS Is iS is ISIISS
(Inflated, Smooth)
IISs
(Inflated, Smooth)
IiSS
(Inflated, Smooth)
IiSs
(Inflated, Smooth)
IsIISs
(Inflated, Smooth)
IIss
(Inflated, Wrinkled)
IiSs
(Inflated, Smooth)
Iiss
(Inflated, wrinkled)
iSIiSS
(Inflated, Smooth)
IiSs
(Inflated, Smooth)
iiSS
(Constricted, Smooth)
iiSs
(Constricted, Smooth)
isIiSs
(Inflated, Smooth)
Iiss
(Inflated, wrinkled)
iiSs
(constricted, Smooth)
iiss
(Constricted, Wrinkled)