determining alleles.. assignment

Please state your question .

I apologize for not adding questions. I was in a hurry and forgot

Please refer to the attachment and the question starts from pg 5-7 only

Pg1-4 is just the introduction. Please help

Thanks Bioman

Exercise # 1: A plant homozygous for long stem (a recessive trait) and heterozygous for terminal flowers (dominant trait) is mated to a plant that is heterozygous for short stem and possess axial flowers. What is the probability of offspring with axial flowers?

A plant homozygous for long stem (a recessive trait) and heterozygous for terminal flowers (dominant trait): hhYy

A plant that is heterozygous for short stem and possess axial flowers: Hhyy

   Y  y
y Yy yy
y Yy yy

What is the probability of offspring with axial flowers? 1/2

---

Possible Gametes from parent 1:

    h h
Y hY hY
y hy hy

Possible Gametes from parent 2:

    H h
y Hy hy
y Hy hy

Step Four:

       hY hY hy hy
Hy HhYy HhYy Hhyy Hhyy
Hy HhYy HhYy Hhyy Hhyy
hy hhYy hhYy hhyy hhyy
hy hhYy hhYy hhyy hhyy

Genotype | Phenotype

HhYy       : Heterozygous for short stem / heterozygous for short stem
Hhyy       : Heterozygous for short stem / possess axial flowers
hhYy       : homozygous for long stem (a recessive trait) / heterozygous for short stem
hhyy       : homozygous for long stem (a recessive trait) / possess axial flowers

HhYy Ratio: 1/4
Hhyy Ratio: 1/4
hhYy Ratio: 1/4
hhyy Ratio: 1/4

Make sense?

Wow thanks alott bioman u saved me

can you please answer the remaining questions

Honestly speaking i love the way you explain.. no words

So, you have two traits: Ear shape & Heart location
Each of these is determined by a different gene with two alleles (that's what the question says).

Spock's dad had pointy ears and a right sided heart while Spock's mom had round ears and a left sided heart. Spock has pointy ears and a right sided heart. So, the first question is, what is Spock's genotype?

Based on the information given, we can't determine this. The possibilities could be that either phenotype for both trait is dominant.

For example:

If pointy ears was dominant, then Spock would be heterozygous, Ee, and would have gotten the recessive allele from his mom, who was ee. But, pointy ears could also be recessive so that his genotype is ee and his mother was heterozygous, Ee.

The same works for the location of the heart gene.

So Spock's genotypes could be:

EeHh
Eehh
eeHh
eehh

depending on which allele is dominant or recessive.

But, I think the author of the question wants you to assume that all Vulcans are homozygous for their two genes and all Earthlings are homozygous for their two genes. If that's the case, then having pointy ears and a right-sided heart have to be dominant and Spock is heterozygous for both, EeHh, since he got the dominant alleles from dad and the recessive alleles from mom.

So, Spock (EeHh) marries and Earth woman who is (eehh) and they have a bunch of kids. If you do the Punnett square, you would predict that they would have:

1/4 with pointy ears and a left-sided heart
1/4 with pointy ears and a right-sided heart
1/4 with round ears and a left-sided heart
1/4 with round ears and a right-sided heart

But, they didn't have this ratio. They had 1/2 pointy ears and right-sided heart and 1/2 round ears and left-sided heart.

The likely reason for this is that these two genes are linked. So in Spock, the E and H alleles are close together on the same chromosome (the one he got from his Vulcan dad) and the e and h alleles were on his other chromsomes (the one he got from his Earthling mom). Then, when Spock passed on chromsomes to his kids, they either got the one with the E and H allele or the one with the e and h allele because the genes are so close together, crossing over cannot occur between the two genes. So Spock never passed on the Eh or eH combination. This is why none of his children showed the mixed phenotypes.

This sounds like Star Trek 

OK--let's assume that each parent is homozygous for both traits (a good assumption). Let's call the parents Sarek and Amanda (their actual character names in the show). Since Spock has his father's phenotype, we know that these two alleles are the dominant ones. So we'll call Sarek PPRR (pointed ears, heart on right side) and Amanda pprr (round ears, left-sided heart). Spock must then be PpRr. His sperm must then pass on one of four genotypes: PR, Pr, pR and pr. The woman's eggs, however, will all be pr. Thus, the possible genotypes for the kids would be PpRr, Pprr, ppRr and pprr in a 1:1:1:1 ratio **if these traits segregate independently**. Then only one-quarter would have pointed ears *and* a right-sided heart; one-quarter would have pointed ears and a left-sided heart; one-quarter would have normal ears and a right-sided heart; and one-quarter would have normal ears and a left-sided heart.

But half of the kids have pointed ears *and* a right-sided heart. So this means that the genes do *not* segregate independently (unlike typical Mendelian genetics).