Читать книгу Horse Genetics - Ernest Bailey - Страница 62

Although the independent inheritance of genetic traits has been emphasized up to now, some genes will tend to be inherited together. The august monk Mendel did not envision the relationship that we now know to exist between genes and chromosomes. But to understand genetics more completely, it is necessary to expand his otherwise elegant theories to include gene linkage.

Any given gene has a particular chromosomal assignment and a place on that chromosome that we call a locus (plural: loci). Occasionally, traits of interest are on the same chromosome and tend to be inherited together more often than they are split apart: these are linked genes. Linked genes can be separated from each other as part of the normal process of chromosome recombination that occurs uniquely during meiosis. At present, the entire genome of the horse has been sequenced and we know the location and sequence of many genes of interest for the horse (Chapter 6 on horse genomics). Yet our understanding of the relationships between the bits of DNA and complex traits like behavior, performance, and many other phenotypic characteristics that we value in the horse remains to be developed.