Benefits and problems with cloning animals

Animal cloning is becoming a useful technique for producing transgenic farm animals and is likely to be used to produce clones from valuable adults. O ther applications will also undoubtedly be discovered in the near future, s uch as for preserving endangered breeds and species. Although cloning promi ses great advantages for commerce and research alike, its outcome is not al ways certain due to high pregnancy losses and high morbidity and mortality during the neonatal period. Research into the mechanisms involved in the re programming of the nucleus is being conducted throughout the world in an at tempt to better understand the molecular and cellular mechanisms involved i n correcting these problems. Although the cause of these anomalies remains mostly unknown, similar phenotypes have been observed in calves derived thr ough in vitro fertilization, suggesting that culture conditions are involve d in these phenomena. In the meantime, veterinarians and theriogenologists have an important role to play in improving the efficiency of cloning by fi nding treatments to assure normal gestation to term and to develop preventa tive and curative care for cloned neonates.