Question

Can someone help me with a biology related question? I'm offering good points!!!!! Help me out please.

Answer 1

First, write out all combinations for the parents:
SsBB:
SB
sB
SB
sB

ssBb:
sB
sb
sB
sb

So now that you know what to put on as the x and y for the Punnett Square, set it up:

     |    SB   |    sB    |   SB    |  sB     
sB | SsBB |  ssBB |  SsBB |  ssBB 
sb | SsBb |  ssBb  |  SsBb |  ssBb 
sB | SsBB |  ssBB |  SsBB |  ssBB 
sb | SsBb |  ssBb  |  SsBb |  ssBb 

Now, listing each possible genotype and the number of times they show up in the square:
SSBB
0 times
SSBb/SSbB
0 times
SSbb
0 times
SsBB/sSBB
4 times
SsBb/SsbB/sSBb/sSbB/
4 times
Ssbb/sSbb
0 times
ssBB
4 times
ssBb/ssbB
4 times
ssbb
0 times

Since there are only 4 genotypes are possible, set up ratios of those four:

SsBB:
4 times/16 total = .25 = 25%

SsBb:
4 times/16 total = .25 = 25%

ssBB:
4 times/16 total = .25 = 25%

ssBb:
4 times/16 total = .25 = 25%

This means that the genotypes have a 25% : 25% : 25% : 25% likelihood.


Now, let's figure out the phenotypes of the 4 genotypes:
SsBB:
Ss = dominant
BB = dominant

SsBb:
Ss = dominant
BB = dominant

ssBB:
ss = recessive
BB = dominant

ssBb:
ss = recessive
Bb = dominant

So we have 2/4 that are S-dominant B-dominant and 2/4 that are S-recessive B-dominant.
This means that the phenotypes are:
2/4 = 50% Thin stripes with black eyes, and
2/4 = 50% Thin stripes with gray eyes.

I hope this helped you out :)