OpenStudy (anonymous):

In gardena peas,the allele for yellow peas is dominant to the allele for green pears.Suppose you have a plant that produces yellow peas,but you dont know whether it is homozygous dominant or heterozygous. What experiment could you do to find out? Draw a punnet square to help you

4 years ago
OpenStudy (anonymous):

Do you know what a genotype is?

4 years ago
OpenStudy (anonymous):

Rr ,rr,RR

4 years ago
OpenStudy (anonymous):

Yes, those are genotypes. Each genotype has 2 alleles. Here's the problem: We have yellow peas. But we don't know the genotype of the yellow peas. Since yellow is a dominant phenotype, what are the two possible genotypes, of yellow peas?

4 years ago
OpenStudy (anonymous):

umm i dont know...

4 years ago
OpenStudy (anonymous):

I'm not a 100% but I believe RR and Rr

4 years ago
OpenStudy (anonymous):

^ Right. DOMINANT alleles are CAPITAL letters. RECESSIVE alleles are LOWERCASE letters. So let's pretend this: A -- Yellow a -- Green We know that a genotype has 2 alleles. Here's a BIG RULE: In a genotype, the Capital letters matter more than the lowercase letters. So, if a pea has the genotype (A a), it's YELLOW. Because there's a Capital A in there. If a pea has the genotype (A A), it's YELLOW. Because there's a Capital A in there. But...if a pea has the genotype (a a), then it's GREEN. Because there are no Capital A's. Just lowercase ( a ). Do you get it so far?

4 years ago
OpenStudy (anonymous):

yea

4 years ago
OpenStudy (anonymous):

Do you know how to make a Punnett Square?

4 years ago
OpenStudy (anonymous):

not really

4 years ago
OpenStudy (anonymous):

You wanna learn?

4 years ago
OpenStudy (anonymous):

yea

4 years ago
OpenStudy (anonymous):

Punnett Squares show us what happens when two parents, each with their own genotypes, get together and breed. Make babies.

4 years ago
OpenStudy (anonymous):

So before we make a Punnett Square, we need the genotypes of two different parents. Can you give me two different genotypes? One GREEN pea plant, and one YELLOW pea plant.

4 years ago
OpenStudy (anonymous):

rr.RR?

4 years ago
OpenStudy (anonymous):

Right. ( r r) would be green. (R R) would be yellow.

4 years ago
OpenStudy (anonymous):

Okay, so here's what the Punnett Square would look like: |dw:1369865183454:dw| The FIRST parent (R R) is on TOP. The SECOND parent (r r) is on the LEFT side.

4 years ago