What is the exact difference between "Balancing Selection" and "Positive Selection"?

Question

[Shangzhe Zhang]

Hi,

It's so confusing that what is the exact difference between "Balancing Selection" and "Positive Selection".

I want to look for the ancient pholymorphism or the ancient balancing selecting genes from the properties of genomic islands. After see some relative papers, I don't know how to do with this. So any suggestions?

Shangzhe.

Answer 1

[Jean-Karim Heriche]

Balancing selection refers to processes that result in maintaining multiple alleles at frequencies different from what would be expected from a neutral model of selection. You can think of it as selecting an allelic compromise between multiple constraints. Positive selection is what people often mean by selection, i.e. the process resulting in an increase in the frequency of the allele that increases fitness.
This paper may be of interest.

[Shangzhe Zhang]

Dear Jean-Karim Heriche ,

Thanks a lot. It's helpful.

Best, Shangzhe.