Genetic Problems

[SunChip]

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1.) What are the chances of a cross between a TtGgSs and a TtGgss producing a tall, green wrinkeled plant?

2.) What are the chances of a cross between TtGGSs and Ttggss plants producing a short, yellow, smooth plant? How do you do these???

The following 3 sets of alleles for bean traits show Mendelian dominant/recessive patterns and found on different chromosomes:

T (tall) t (short)
G (green g (yellow)
S (smooth) s (wrinkled)

Thanks in advance!

 

[RogueUnicorn]

it's straight up probability.

1) for the T gene, chance of T trait is 3/4. Same for G traid. s trait is 1/2. therefore the total probability is 3/4*3/4*1/2=9/32
2) similarly, t trait here is 1/4, yellow is 0 (since green is dominant and all offspring are heterozygous) and smooth is again 1/2. total probability is 0.

do the punnett square if you don't believe me. also, a triple gene assortment on an MCAT would happen pretty much never

 

[kidkay]

Yup, that's right, got beaten to the post....

it's straight up probability.

1) for the T gene, chance of T trait is 3/4. Same for G traid. s trait is 1/2. therefore the total probability is 3/4*3/4*1/2=9/32
2) similarly, t trait here is 1/4, yellow is 0 (since green is dominant and all offspring are heterozygous) and smooth is again 1/2. total probability is 0.

do the punnett square if you don't believe me. also, a triple gene assortment on an MCAT would happen pretty much never

 

[unique135]

Crap...need to review this...

Tt x Tt
Chances of producing tall: TT + Tt + tT = 1/4 + 1/4 + 1/4 = 3/4

Similarly, Gg x Gg
Chances of producing green: GG + Gg + gG = 1/4 + 1/4 + 1/4 = 3/4

Ss x ss
Chances of producing wrinkled: ss + ss = 1/2


Overall, chances of producing tall, green and smooth is 3/4 x 3/4 x 1/2 = 9/32


Same way other one