Testcross problem

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basketball fan
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Testcross problem

Post by basketball fan » Fri Mar 03, 2006 10:31 pm

When you do a testcross, what is the genotype of the individual is crossed

with the unknown.

I think it homozygous recessive

Am i correct.

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Khaiy
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Post by Khaiy » Fri Mar 03, 2006 11:59 pm

Yes, you cross your experimental generation (the one whose genotype you'd like to find) with a homozygous recessive individual.

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Enzyme
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Post by Enzyme » Sat Mar 04, 2006 10:46 am

Yes, a test cross is the cross between the experimental (the individual you don't know its genotype) and the recessive homozygous.

If the result of the test cross is that it produce two different phenotypes, it means that the unknown genotype (experimental) is heterozygous for that treat. If the result is the appearance of only one phenotype, it means that the experimental is homozygous.

Test cross verify that the hypothesis of that alleles are in pairs (and their segregation is produced in the formation of gametes) is true.

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Nithin
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Post by Nithin » Sun Mar 05, 2006 3:21 pm

Yeah,
Test cross is a kind of back cross where a cross is performed between the unknown experimental and specifically a homozygous recessive. The resultant ratio will be always 1:1.

12345
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Post by 12345 » Wed Mar 08, 2006 10:10 am

I beg to differ. Will a test cross always yield 1:1 ratio. Actually what is test cross. Is it actually a cross between a recessive parent and the F1 generation??

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MrMistery
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Post by MrMistery » Wed Mar 08, 2006 7:41 pm

no, that is a back cross.
In a test cross you cross your individual with a homozygous recessive. And if it is an F1 individual than it would yield a 1:1 ratio(firt rule of inheritance)
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