The evolution and
development of sinistral snails
Angus Davison and Maureen Liu
Institute of Genetics/School of Biology
University of Nottingham
The maternal inheritance of chirality
The phenotype of offspring depends upon the
genotype of their mother. D = dominant dextral
allele; S = recessive sinistral allele.
Only five phenotype/genotype combinations are possible. Dextral snails can be of genotype
DD, DS or SS. Sinistral snails can be genotype DS or SS; they can not be DD because the
mother must have carried the dominant dextral allele.
Dextral is dominant in this scheme but not always so (e.g. Partula)
Crampton 1890s; Boycott & Diver 1923; Sturtevant 1923
Nodal – backwards?
Candidate gene?
Snails (Lymnaea stagnalis) in culture –
Direct – gene products
Indirect – mapping
Angus Davison, Aziz Aboobaker and
Maureen Liu (University of Nottingham)
Prof. Mark Blaxter, Dr John Davey (University of Edinburgh)