A Genetics Question on F2 Genotypes.

[Lazerous]

Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is self fertilized. If the capital letters represent dominant, independently assorting alleles:
a) how many different genotypes will occur in the F2?
b) what proportion of the F2 genotypes will be recessive for all five loci?

The answers are
a) 3^5= 243
b) 1/243

But I don't know how they got them. Namely the first question. Please help.

---

Members don't see this ad.

 

[Danny289]

Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is self fertilized. If the capital letters represent dominant, independently assorting alleles:
a) how many different genotypes will occur in the F2?
b) what proportion of the F2 genotypes will be recessive for all five loci?

The answers are
a) 3^5= 243
b) 1/243

But I don't know how they got them. Namely the first question. Please help.

you know for F1 you will have: AaBbCcDdEe and for F2 you will have:
AaBbCcDdEe X AaBbCcDdEe because you have independently assorting just do Aa X Aa and Bb X Bb and ......independetly then
for Aa X Aa you will have AA & (Aa, Aa) & aa and go on for other alleles thats means 3 kind genotype for each because you have 5 set, it will be 3^5 as you see from each set you have 1 set recessive( for example aa just rember from 4 sets two of them are same!) for second part will be:
(1/3)5. hope it helped
🙂

 

[Lazerous]

you know for F1 you will have: AaBbCcDdEe and for F2 you will have:
AaBbCcDdEe X AaBbCcDdEe because you have independently assorting just do Aa X Aa and Bb X Bb and ......independetly then
for Aa X Aa you will have AA & (Aa, Aa) & aa and go on for other alleles thats means 3 kind genotype for each because you have 5 set, it will be 3^5 as you see from each set you have 1 set recessive( for example aa just rember from 4 sets two of them are same!) for second part will be:
(1/3)5. hope it helped
🙂

Sweet! I got it. Thank you. 👍

 

[mx41]

AABBCCDDEE x aabbccddee

AAaaBBbbCCccDDddEEee

For A... possible gametes : AA, Aa, aa
So that's three gametes per letter set. There are 5 letters
So use the formula:

(# of gametes/set)^number of set
= 3^5

For second part:

Think about the chance you can get aa in the letter A set..
... possible gametes : AA, Aa, aa
1/3 chance because aa is only one gamete in the A gamete set.

There are 5 letter sets so
(1/3)^5

 

[Lazerous]

Thanks for the reply!

I have another question now.

True/False. The Law of Segregation pertains to separation of sister chromatids in meiosis.

The answer is "False." I don't seem to get why this is the answer, though. Anybody care to explain?

 

[Lazerous]

True/False: With complete dominance, the phenotypic ratio equals the genotypic ration in the F2.

The answer is "False"

Hmmmm...never mind, I think I got it.

Complete dominance: P1 is AA x aa --> F1 is Aa x Aa and F2 will give these results:
Genotypic ratio= 1(AA):2(Aa):1(aa) and Phentotypic= 3:1

Correct?

EDIT: Can someone please answer my question above this one.

 

[Danny289]

True/False: With complete dominance, the phenotypic ratio equals the genotypic ration in the F2.

The answer is "False"

Hmmmm...never mind, I think I got it.

Complete dominance: P1 is AA x aa --> F1 is Aa x Aa and F2 will give these results:
Genotypic ratio= 1(AA):2(Aa):1(aa) and Phentotypic= 3:1

Correct?

EDIT: Can someone please answer my question above this one.

AA, 2Aa, aa =====> genogtype===> 1:2:1
phenotype: 3:1
you are right. 🙂

 

[Lazerous]

AA, 2Aa, aa =====> genogtype===> 1:2:1
phenotype: 3:1
you are right. 🙂

I really do appreciate it. Any idea on this question, though?

True/False. The Law of Segregation pertains to separation of sister chromatids in meiosis.

The answer is "False."

 

[Danny289]

I really do appreciate it. Any idea on this question, though?

True/False. The Law of Segregation pertains to separation of sister chromatids in meiosis.

The answer is "False."

think about linked genes they don't folow the "Law of Segregation" and most of the time we have linked genes. maybe you remeber this comon question from Genetics : "why Mandel was lucky in his experiments?" 🙂
in addition law of segration is about genes not sister chromatids.