Re: Can one cause a characteristic to become sex-linked?

Hi Charlie,

Interesting question! The sex chromosomes generally consist of two parts: a freely recombining pseudoautosomal region and a non-recombining region containing the sex determination genes. In order for a gene to be sex linked it must be in the non-recombining region otherwise its linkage with the sex determination gene could become broken by recombination in the heterogametic sex.

While it's theoretically possible for chunks of the genome to be transferred from an autosome to a sex chromosome during recombination (= crossing over), this could only occur within the pseudoautosomal region where recombination occurs. The transferred gene would now be located on the sex chromosome, however, it would not be sex linked since recombination between this gene and the sex determining gene could still break the linkage between them. A gene is sex linked only if recombination never occurs between that gene and the gene which determines sex (and therefore they are always inherited together). Recombination cannot be used to move a gene into this region since recombination never occurs there.

So in summary, no it's not possible to use recombination to make a trait sex linked, and therefore no one has attempted this experiment. I'm sorry about the technical nature of this answer. If any of the jargon I've used is unfamiliar to you take a look at any good college level textbook on genetics or molecular biology. My own favourites are Molecular Biology of the Cell by Bruce Alberts and Recombinant DNA by James Watson.

I hope this answers your question.

Regards,

Rob Cruickshank