2.3 Punnett Square
Don’t get scared by the fancy name It is nothing new but simply an organized way of presenting what we already know.
Our first pairing is
Green split Blue X Green
We already know that the genes in Green split Blue are denoted by GB and the green has the genes GG.
We put this information first in the table below fig 2.
Now it is simply a matter of filling the remaining cells to arrive at the outcome. The Mother will contribute either a G or a B gene. The father only has 2 copies of the G gene. We combine the letters in the row and the column to arrive at the outcomes. We see that two of the cells show GG and the other two show GB. So half of the offspring will be Green GG and the other half Green split Blue.
The second pairing is
Green Split Blue X Green Split Blue
We put this information in the table and we get fig 3
We now see that one cell has GG, two cells have GB (GB and BG are the same genetically) and one cell has BB. So our result from this pairing is
1/4 or 25% Green
2/4 or 50% Green Split blue
1/4 or 25% Blue
Homework
-------------
Question:
1) Is it possible for two blue birds to breed a green offspring?
2) Is it possible for two green birds to breed a blue offspring?
Our first pairing is
Green split Blue X Green
We already know that the genes in Green split Blue are denoted by GB and the green has the genes GG.
We put this information first in the table below fig 2.
Now it is simply a matter of filling the remaining cells to arrive at the outcome. The Mother will contribute either a G or a B gene. The father only has 2 copies of the G gene. We combine the letters in the row and the column to arrive at the outcomes. We see that two of the cells show GG and the other two show GB. So half of the offspring will be Green GG and the other half Green split Blue.
The second pairing is
Green Split Blue X Green Split Blue
We put this information in the table and we get fig 3
We now see that one cell has GG, two cells have GB (GB and BG are the same genetically) and one cell has BB. So our result from this pairing is
1/4 or 25% Green
2/4 or 50% Green Split blue
1/4 or 25% Blue
Homework
-------------
Question:
1) Is it possible for two blue birds to breed a green offspring?
2) Is it possible for two green birds to breed a blue offspring?
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