Developing Work

One of the most interesting turns has been the re-interpretation of the difference between 'cliff' and 'boulder' forms of the intertidal snail Littorina saxatilis as meaning a possible signal of speciation happening (26). The difference between these animals (we call them 'H' and 'M' forms because of their high and mid-shore positions) is now established in terms of shell shape (23, 3), DNA polymorphisms (21, 1), and (crucially) the behaviour of the animals themselves - for mating, they prefer a partner of the same morphological type (15).

This put the biogeography of shell shape, and the further exploration of the nature of small barnacle-dwellers, on hold while work on this aspect has been developed.

AFLPs and variation in Littorina: for analysis and interpretation of our data, Roger Butlin (now in Sheffield) wrote a simulation program. This program was referred to in our paper in Journal of Evolutionary Biology, and is available here, together with some explanatory notes (The WINKLES program.pdf). If you want to use this, download the zip file and extract it. Any problems with downloading, please notify John Grahame.

Please be aware! This software is made available should you want to use it in research. Such use is at your own risk; you must not use the software commercially; you are free to copy the software for other users provided you pass on this warning notice.

We may have a new subject for speciation studies, the first paper exploiting this system used AFLPs (see above) of several populations to show that there is differential gene flow between H and M animals is Wilding et al., 2001 (2). Collaborating with Roger Butlin, I am developing this study for the future: In April of 2003 Henry Wood joined the group on BBSRC funding to take this work further. In September 2004 Catherine Sinfield joined as a NERC-funded PhD student.