Test Cross Questions from DAT Achiever

[RHONDAROBINSON]

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Could someone help me with this question?

In a plant, blue petal (B) is dominant to white petal(b): and long stem (L) is dominant to short (l). Determine parental genotype If you have:

299 blue petal long stem
302 blue petal short stem
103 white petal long stem
98 white petal short stem.

What is the parental genotype? DAT Achiever got BbLI XBbll or BbllXBlLI. Please explain this in simple terms. I have done a test cross and do not get this. Thanks in advance.


rr

 

[tinman831]

There is a 3:1 ratio of blue to white petals. The only genotypes to produce that ratio is a heterozygote cross with a heterozygote (Bb x Bb). There's a 1:1 ratio of long to short stem plants and the only genotype to produce this result is a heterozygote cross with a homozogous recessive (Ll x ll). This results in parents who have a BbLl and Bbll genotypes. I don't know where that second answer came from though.

Could someone help me with this question?

In a plant, blue petal (B) is dominant to white petal(b): and long stem (L) is dominant to short (l). Determine parental genotype If you have:

299 blue petal long stem
302 blue petal short stem
103 white petal long stem
98 white petal short stem.

What is the parental genotype? DAT Achiever got BbLI XBbll or BbllXBlLI. Please explain this in simple terms. I have done a test cross and do not get this. Thanks in advance.


rr

 

[KTDMD]

There is a 3:1 ratio of blue to white petals. The only genotypes to produce that ratio is a heterozygote cross with a heterozygote (Bb x Bb). There's a 1:1 ratio of long to short stem plants and the only genotype to produce this result is a heterozygote cross with a homozogous recessive (Ll x ll). This results in parents who have a BbLl and Bbll genotypes. I don't know where that second answer came from though.

Good explanation, tinman. The second answer should be BbllXBbLI, which is only a switch of genotypes for both genders. OP has probably mistyped them as "BbllXBlLI".

The apt of getting this question resolved also reflects your ability to handle the QR section, specifically for word problems involving factorization, with great speed and accuracy. Pay extra attention to it, which will only do good for your future DAT scores.