I know very little on this topic so please bare with me if this seems very idiotic. How could I selectively breed fruit flies? I know this is very simple but I can't seem to get it right.
It’s not idiotic, just puzzling. Drosophila is one of the most popular model organisms for genetic and developmental biology research
ever. There’s a huge amount of info out there on teh interwebs. Have you tried looking at the external links at the bottom of the
Wikipedia Drosophila entry? Resources like
FlyBase and
The WWW Virtual Library: Drosophila would surely have some basic breeding tips and tricks.
Also is there a way to genetically modify or mutate them?
Certainly. Endless people’s careers revolve around mutating them.
The age-old method of introducing random point mutations is to simply use a chemical mutagen like EMS (ethyl methane sulphonate). This is the classic unbiased forward genetic approach whereby you generate a phenotype of interest then work backwards to determine what gene has been mutated. This pivotal technique has contributed enormously to our understanding of embryonic developmental processes. This technique can generate hypomorphic alleles as well as null alleles.
Another method of gene inactivation is to make random insertions using P elements (transposable elements). They insert randomly in the genome, but because you introduce a known genetic marker you can screen for instances where the P element has inserted into your gene of interest.
You can make transgenic flies by integrating an expression construct into the genome. I’m not sure how this is done in Drosophila. It might utilise transposable elements or you may be able to simply inject the DNA into fertilised eggs. Regardless, it’s a powerful technique that can direct tissue and temporal specific expression of genes. The GAL4-UAS system originally devised for yeast has been extensively utilised in Drosophila to create driver and response strains that make transgenics in Drosophila even more useful.
I’m not aware that targeted genetic modifications (like homologous recombination in the mouse) has been achieved in Drosophila yet, but I might be wrong about that.
Also, I seem to recall that gene knockdown effects of RNAi in invertebrates like Drosophila and C.elegans can actually be heritable. I’m not sure of the mechanism behind this.
Has this been enough info?
