<p>A number of proteins involved in the transport of sulphate across a membraneas well as some yet uncharacterised proteins have been shown [<cite idref="PUB00005419"/>, <cite idref="PUB00003771"/>] to be evolutionary related.These proteins are:<ul><li> <taxon tax_id="5141">Neurospora crassa</taxon> sulphate permease II (gene cys-14).</li><li>Yeast sulphate permeases (genes SUL1 and SUL2).</li><li>Rat sulphate anion transporter 1 (SAT-1).</li><li>Mammalian DTDST, a probable sulphate transporter which, in human, is involved in the genetic disease, diastrophic dysplasia (DTD).</li><li>Sulphate transporters 1, 2 and 3 from the legume <taxon tax_id="37660">Stylosanthes hamata</taxon>.</li><li>Human pendrin (gene PDS), which is involved in a number of hearing loss genetic diseases.</li><li>Human protein DRA (Down-Regulated in Adenoma).</li><li>Soybean early nodulin 70.</li><li> <taxon tax_id="562">Escherichia coli</taxon> hypothetical protein ychM.</li><li> <taxon tax_id="6239">Caenorhabditis elegans</taxon> hypothetical protein F41D9.5.</li></ul> </p><p>These proteins are highly hydrophobic and seem to contain about 12 transmembrane domains.</p>