[HELICONIUS] W-linked markers

[Alexie Papanicolaou]

Hi Jamie

if you sequenced a male, then there will be nothing W-specific in the
genome... there will shared elements though which could be
over-represented in the W.

your question is much easier though. we've had 3 approaches that worked.

Hard, molecular approach
Dissecting the w of a butterfly, cloning and sanger sequencing
W-specific repeats (Fukova in Applied Entomology)
Also you can try a AFLP bulk segregation analysis on a family of male
and females with the parents. markers on mum and daughters are w linked.

Easy, lethal physiological approach
Chop it up. There will be two large (yellow or white) bodies in the
males. Testis... for us it works well with L3+ even though our moth
larvae are much smaller than heliconius larvae

Fiddly, fool-proof cytogenetic approach
take a spot of hemolymph (no need to kill it). make a squash preparation
with lactic orcein. look under 40x. if the nuclei have a big black spot,
it's the W body and it's a female... Let me know if you need the
protocol (should be in above paper). It's not that fiddly when you learn
it and you can process lots of larvae in a day (you can do the
microscope work another day)

cheers
a


On Wed, 2010-04-14 at 11:57 +0100, Jamie Walters wrote:

> Hello all,
> 
> I'm curious to know if anyone has had any success (or informative  
> failures...?) with developing W-linked markers for Heliconius (or any  
> butterfly that would be near enough to be useful).
> 
> Or, alternatively, if anyone has any particularly clever ideas for  
> mining the existing genome data for candidate regions I'd be keen to  
> hear them.
> 
> I'm simply interested in being able to sex juveniles and pupae.
> 
> 
> Thanks very much,
> 
> Jamie
> 
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