SELECTION AND CLONING METHODS

摘要

Selection and cloning methods are disclosed that are effective for the selective multiplication of desired animals, for instance livestock animals. These methods can be used to expand populations of animals, and are particularly useful for duplicating animals selected based on traits that are measured after the animal is deceased. Certain embodiments include techniques useful for selecting a desirable bovine animal (e.g., desirable steer) based at least in part on a measurable carcass trait. Also described are specific cloning techniques that involve repetitive (for instance, two) cycles of cloning, such as nuclear transfer cloning. In specific embodiments, a two-step cloning system is described, in which the nuclear donor of the first cloning cycle is an adult fibroblast cell and the nuclear donor of the second cloning cycle is a fetal fibroblast harvested from a fetus that arose from the fist cloning cycle.