Back-crossing

[Hades]

So, with backcrossing, how am i able to determine which gene the locus is on? Is the gene of interest going to be expressed with only genes that are not present on the chromosome the gene is on?

for example, if i had chromosomes 1 and 2 and wanted to know which chromosome mutation black was on. breed the two parentals, then cross an F1 with the parental female. The resulting offspring produce phenotypes, of these, black mutation is present only with certain phenotypes and alone with itself.

If this were in drosophila, how do i interpret these results?

[Mokele]

You need a second mutation whose location is known. For example, if you know "leggy" is on chromosome one, you can see if "black" co-occurs with leggy more often than chance, and if so, they're on the same chromosome. It's not possible with just one gene; you need more.

 

Mokele