Most patients die by age 3. Referring to an organism whose genome has been altered by the insertion of foreign DNA, usually with the intention of producing a different phenotype. United Nations Educational, Scientific and Cultural Organization. The nucleotide sequence of the most prevalent form a particular gene in a species. A sex chromosome.
Female mammals have two X chromosomes.
Males have an X and a Y chromosome. These chromosomes can carry a much larger segment of foreign DNA than can other conventional cloning vectors. A fertilized egg, before it begins dividing.