title: Left-right development: mammalian phenotypes and conceptual models.
abstract: Consistent left-right asymmetry in a population requires a special kind of developmental specification. Models of this process must account for the complex phenotypes seen when left-right is abnormal. In some human and mouse mutations, there appears to be a randomisation of global situs to either solitus or inversus, whereas in the inv/inv mouse essentially all are inversus. However, in these and all additional examples there are frequently other anomalies, including symmetry (isomerism) and discordance between organs (heterotaxia). Current models invoke a molecular chiral referent as the source of the primary handed information. We describe a new two-gradient model which accommodates all defects of situs whilst leaving the primary asymmetry unaltered.
authors.affiliation: Birmingham Children's Hospital, Ladywood Middleway, UK.
authors.forename: A
authors.initials: A
authors.lastname: Lander
authors.forename: T
authors.initials: T
authors.lastname: King
authors.forename: N A
authors.initials: NA
authors.lastname: Brown
mesh_terms: D000818:Animals; D019521:Body Patterning; D000013:Congenital Abnormalities / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D008322:Mammals; D051379:Mice; D008954:Models, Biological; D010641:Phenotype; D014428:Twins, Conjoined