Gene linkage/recombination

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AntonFreeman

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When the question says gene for color and size are located on same chromosome, how do we know which alleles are together? I am looking at TPR books. Some questions do not tell you which alleles are linked together.
 
When the question says gene for color and size are located on same chromosome, how do we know which alleles are together? I am looking at TPR books. Some questions do not tell you which alleles are linked together.

Don't take my word on this, but I believe if the percent recombination is 50% or greater, then they are considered to be unlinked because they have a higher probability of swapping places with a neighboring chromatid. A lower percent recombination indicates they are more likely to remain linked together.
 
When the question says gene for color and size are located on same chromosome, how do we know which alleles are together? I am looking at TPR books. Some questions do not tell you which alleles are linked together.

The further the genes are the more chances of recombination. Here's a brief description of how this works

2 Genes Far apart on the same chromosome leads to crossing over between genes in every meiosis there is a 50 % recombinant progeny and the genes are defined as Unlinked.
2 Genes on different chromosomes have independent segregation of different homologous pairs and also have a 50 % recombinant progeny and the genes are unlinked.
When 2 genes are intermediate distance apart on SAME chromosome then crossing over occurs between genes in some meiosis which leads to < 50 % recombinant progeny. Genes are classified as partially linked.
When 2 genes are VERY close together on SAME chromosome No crossing over occurs there's 0 % recombination and genes are classified as linked.

So chances of recombination go any where from 0-50 % depending on the situations that I listed above. There WILL NOT be recombination more than 50 % that is the max
 
Thanks for responses. But what I saw on TPR was that unless specified, it seemed like dominant alleles are always on same chromosome and recessive alleles are linked together (ex BG bg).
 
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