The gene in question belongs to a retrovirus and the embryos in question belong to sheep .
此项研究中的基因属于一种逆转录病毒,而胚胎则属于绵羊。
The first to be discovered is the remnant of a retrovirus that invaded the primate genome a little less than 40 million years ago and gave rise to what is known as the w family of ervs .
They again used a retrovirus to introduce four genes , this time experimenting with adult mouse liver and stomach lining cells .
他们再次使用逆转录病毒导入四种基因到成年小鼠肝脏和胃粘膜细胞内。
The koala retrovirus , which infects and alters the animal 's dna , has been linked to a variety of diseases and medical problems , including leukemia , bone marrow failure , cancer and aids-like immune deficiencies .
Usually it is an extension of the normal infectious process , when a retrovirus infects a blood cell , such as a lymphocyte . But if the virus happens to get incorporated in a chromosome in the host 's germ line ( sperm or egg ) , it can become part of the genome of future generations .