Explain what loss of heterozygosity is...

Loss of Heterozygosity is when (in a diploid organism) one allele of a particular gene becomes lost, and then the single remaining gene somehow becomes defective/mutant. Then the expression for this affected gene becomes lost. The prime example of this would be retinoblastoma, where one can get retinal cancer...

Post Merge: 9 years ago

I'm hoping one of the administrators can help chime in on this..

You haven't posted a question, confused on what you need...

Imagine we have some organism where having phenotype aa makes organisms more able to deal with heat but less with cold, while Aa and AA deal better with cold but not with heat.

If we have a popultion with AA and Aa and the temperature goes up, all of a sudden more of the aa organisms will survive compared to the AA and Aa organisms, but there will be enough aa organisms (produced by the Aa and the aa organisms) that the population will continue to exist.

If the temperature swings back to cold after a long time, because of the Aa and AA guys dying out, the aa won't have a mutation around so that their offspring will be able to deal with cold.

If there is heterozygosity, there is a wider range in possible offspring. A wider range in possible offspring means a wider range of conditions that offspring can survive in, usually.