Reproductive biotechnology in farm animals goes genomics
The breeding of domestic animals has a longstanding and successful history, starting with domestication several thousand years ago. Modern animal breeding strategies, predominantly based on population genetics, artificial insemination (AI) and embryo transfer (ET) technologies led to significant increases in the performances in domestic animals and are the basis for the regular supply with high-quality animal-derived food at acceptable prices. A recent addition to this arsenal of technologies is the separation of spermatozoa into X-and Y-chromosomes bearing populations by means of flow cytometry, which is going to be transferred into commercial cattle breeding. Moreover, reproductive biotechnologies are currently being complemented by new measures of molecular genetics. The genomes of several domestic animals have been sequenced and annotated. Important uses of genomic data include improving selective breeding strategies, studying expression patterns (transcriptomics or proteomics) and the production of transgenic animals tailored for specific production purposes. The technology for the production of transgenic animals, either by additive gene transfer or by selective deletion (knockout), has been advanced to the level of practical application. A crucial step in this context was the development of somatic cell nuclear transfer (SCNT) cloning, which has replaced the previously used rather inefficient method of microinjection for producing transgenic animals. In this review, we discuss recent advances in important areas of animal biotechnology related to agricultural applications, including sperm sexing, somatic cloning, genome and transcriptome research, transgenesis and recombinant DNA vaccines with emphasis on large domestic species.