Figure 1
From: Diaphanous gene mutation affects spiral cleavage and chirality in snails
Positional cloning identifies Lsdia1 as a candidate gene for chirality determination.
(a) Genetic and physical map of the snail chirality locus. Genetic distances are in cM (1,600 gametes) on the first line of the figure. Closely linked AFLP markers are shown vertically, and black horizontal bars represent BAC clones. Seven BAC clones indicated in red numerals were sequenced and two contigs (Contig 1 and 2) were assembled. There is a small gap (<100 bp) between the two contigs in the current physical maps. (b) Upper panel: Schematic representation of 15 candidate genes for snail-handedness determination. Maternally expressed genes are shown in red. Lower panel: Lsdia1 exon-intron structure and the causative mutation. (c) The mutation site responsible for snail chirality is indicated. (d) Schematic representation of Dia1 structure of three Lymnaea snails (dextral and sinistral L. stagnalis and dextral L. peregra), as well as Dia2 of dextral L. stagnalis and L. peregra. Lymnaea Dia1 contains six conserved domains: Rho GTPase-binding domain (GBD) (IPR010473), diaphanous inhibitory domain (DID), dimerization domain (DD), proline-rich formin homology 1 (FH1) domain, formin homology 2 (FH2) (IPR015425) and diaphanous autoregulatory domain (DAD) (IPR014767). The c.del184C mutation in sinistral L. stagnalis generates a premature stop codon (p.Leu62Serfs*24) in the Lsdia1 mRNA. The amino acid length of Dia1 and Dia2 proteins, and the amino acid sequence homologies are shown at the far right.
