PMC:1852721 / 28436-29776 JSONTXT

{"project":"2_test","denotations":[{"id":"17357067-9235169-2054046","span":{"begin":174,"end":176},"obj":"9235169"},{"id":"17357067-13932119-2054047","span":{"begin":428,"end":433},"obj":"13932119"}],"text":"Genetics was defined by William Bateson as the science of biologic variation. It can also be defined simply as the study of inheritance, and genomics as the study of genomes.26 However genetics is defined, one of its main objectives is to identify specific genetic elements underlying specific phenotypes—to connect phene and gene. The first of the three original phenotype catalogs, that for the X chromosome, was published in 19626 as one of three parts of a review “On the X chromosome of Man.” The catalog of X-linked traits was assembled as an assessment of the gene content of the X chromosome. The list of traits, most of them disorders or diseases, was compared to a photographic negative from which a positive picture of the genetic constitution of the X chromosome could be derived. Although the second catalog, that for autosomal recessive traits, was assembled for utilitarian purposes—that is, as a resource in the identification of new recessive diseases in inbred groups such as the Amish—the “gene behind the phene” was always in mind, and no more than one entry per gene was wittingly made from the beginning of MIM in the 1960s. However, in the age before human molecular genetics, the one gene–several phenotypes and one phenotype–several genes complexity meant that the one gene–one entry rule was often on shaky ground."}