Punnett Squares?

Question

I have never done punnett squares and I do not know how to explain what I need. So heres my best shot I hope someone can help me!

Assume that “S” represents the dominant trait of having long leaves, and “s” represents the recessive short-leafed trait in a plant. In the parental generation, you cross a homozygous long-leafed plant with a homozygous short-leafed plant. Draw a Punnett square illustrating this cross, and give the genotypes and phenotypes of the F1 generation.

F1:AaBbCc x AaBbCc

lowercase= very light uppercase= very dark

Answer 1

AaBbCc x AaBbCc

... and your teacher wants a Punnett square, then it's going to have to be 8 rows and 8 columns.

Show all the possible gametes from each parent.
Each gamete must have an a, b, and c.

ABc
ABC
AbC
Abc
aBc
aBC
abC
abc

all 8 of these gametes will be on a colum down and a colum across to make 64 squares.

Then each box of the Punnett square will have 6 letters again:
There's no way to show you the square in this word-processing format. Just give it a try.

also if you want me to show you how to do it, or do it for you online, just IM me on aim @ ebrady247

Answer 2

You have two different problems here.

In the first problem:
homozygous long = SS
homozygous short = ss

Parents SS x ss
Gametes S S s s
Put first parent's gametes on the side of the square and second parent's gametes on the top to make the column headings.

Each of the four boxes in the Punnett square will have Ss (that's the genotype because it tells what the genes say) and will be long-leaved (that's the phenotype because that's the form of the trait that they exhibit).


In the second problem, you have a case of polygenic inheritance in which several pairs of genes govern the trait. The individuals AaBbCc are each medium darkness because they have three uppercase and three lowercase letters each.

The offspring from these two individuals could have any number of uppercase letters. They could get A from each parent, B from each, and C from each: AABBCC and be the darkest possible, or they could get AABBCc and be one step lighter -- clear down to the possibility of being aabbcc and being as light as possible.

Answer 3

This is a pretty simple one if you just take a deep breath.
Steps:
1. Draw a box with 4 smaller squares in it.
2. Review your terminology to remember what homozygous means
Long leaf (dom)=SS
Short leaves (rec)= ss
3. On the left side write out one of the seperated parental alleles (each letter, upper or lowercase S= 1 allele)
4. On the top write out the other seperated parental alleles
So it should look like this
s s
S__|__
S |
5. Now add copy the letters down or across the row they are each in
6. Your resulting square will look like this
Ss|Ss
Ss|Ss
7. So what does this mean?
They all have the same genotype (heterozygous) and the same phenotype (they all look like they have tall leaves)

You may want to try a couple different simple squares
what if you crossed a Ss with an Ss?
or a ss with and Ss?

What would teh resulting genotypes and phemotypes be here?

Have fun with this stuff, it is kinda cool when you think about it a bit.

Answer 4

Put two big S's across the top
Put two small s's down the sides
You will come up with Ss when you cross the two, in all four middle squares.

Genotypes: Ss
Phenotypes: 100% will be long leafed plants, with one dominant and one recessive gene