im in pre ap biology and i need help with the 16 sqared punnet squares!!! and how to find out the phenotype?

Question

ratios are hard also. I dont understand how to put the genotype ratios on the punnett squares. the 16 squared ones are hard some one help me!!! please!!!

Answer 1

If you're doing 16 squares, then you're doing a dihybrid cross.

Make the gametes from the parents like this:

Parent: AaBb
Gametes: AB Ab aB ab
(Just match each A or a with each B or b to show all the possible gametes.)

Put the gametes from one parent down the side of the Punnett square and put the gametes from the other parent across the top.

Then the 16 boxes get the gamete you see to the far left and the gamete from the top of its column. If the gamete from the left says Ab, and the gamete from the top says ab, then in the box you write Aabb. Be sure you pair up the a's and pair up the b's.

In order to get a phenotype ratio, you just have to tally how many of each phenotype there are. The numbers have to add up to 16 unless you can reduce them.

If both parents are heterozygous for both traits (AaBb x AaBb), then the phenotype ratio will be 9:3:3:1 where it's 9/16 of the offspring having both dominant forms of the traits, 3/16 having the dominant form of the first trait and the recessive form of the second trait, 3/16 having the recessive form of the first trait and the dominant form of the second trait, and 1/16 having the recessive form of both traits.

Look at some sample crosses on web pages.

Answer 2

see you later as H is thoroughly dominant, then definite, not one of the offspring interior the first era would have the ailment; they'd purely be organizations of the gene. interior the 2d era although, there is an chance that countless the offspring will be diseased.

Answer 3

the phenotype are the physical characteristics that show up (what you can see).

Answer 4

http://en.wikipedia.org/wiki/Punnet_square#Typical_dihybrid_cross