tailieunhanh - Environmental Biotechnology - Chapter 9

Genetic Manipulation Gen đã được chế tác bởi người đàn ông trong một thời gian rất dài, đó là nếu chọn lọc giống, đã được thực hành trong nhiều thế kỷ trong lĩnh vực nông nghiệp và các nơi khác để phát triển các đặc tính mong muốn trong động vật, thực vật thuần dưỡng và được coi là thao tác, vì nó một cách đúng đắn nên. Thậm chí từ những ngày đầu của Gregor Mendel, các nhà sư Moravian và tiên phong trong phân tích di truyền, thực vật được tạo ra để mang lại những đặc điểm. | 9 Genetic Manipulation Genes have been manipulated by man for a very long time that is if selective breeding which has been practised for centuries in agriculture and elsewhere to develop desirable characteristics in domesticated animals and plants is to be considered as manipulation as it rightly should. Even from the early days of Gregor Mendel the Moravian monk and pioneer of genetic analysis plants were bred to bring out interesting useful and sometimes unusual traits. Many of these are now lost to classical plant breeders because of divergence of strains leading to infertile hybrids. One of the joys of genetic engineering is that in some cases ancient genes may be rescued from seed found in archaeological digs for example and reintroduced by transfer into modern strains. It has been proposed that the exchange of genetic information between organisms in nature is considerably more commonplace than is generally imagined Reanney 1976 and could explain the observed rates of evolution. In bacteria the most likely candidates for genetic transfer are plasmids and bacteriophage and since eukaryotes lack plasmids their most plausible vectors are eukaryotic viruses. This of course is in addition to DNA transfer during sexual reproduction. Current knowledge would suggest that exchange involving a vector requires compatibility between the organism donating the genetic material the vector involved and the recipient organism. For example two bacteria must be able to mate for plasmid transfer to take place or if a virus is involved as a vector it must be able to infect both the donor and recipient cells or organisms. However there is evidence to suggest that this view is somewhat naive and that there is considerably more opportunity for genetic exchange between all cells prokaryotic and eukaryotic than is popularly recognised. This idea proposed by Reanney 1976 is developed in Chapter 3. Bacteria are notorious for their ability to transfer genes between each other as the .