1 / 8

Selective Breeding

Selective Breeding. Over 1000’s of years mankind has grown plants and domesticated animals. Characteristics have been selected for repeated breeding e.g - milk yield in cattle - meat yield in poultry and cattle - woolly fleece in sheep - corn seeds with high oil or protein content

rufusk
Download Presentation

Selective Breeding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Selective Breeding • Over 1000’s of years mankind has grown plants and domesticated animals. • Characteristics have been selected for repeated breeding • e.g - milk yield in cattle • - meat yield in poultry and cattle • - woolly fleece in sheep • - corn seeds with high oil or protein content • Only members of a species with the required characteristic are allowed to breed

  2. Genetic engineering • Each bacterial cell has a chromosome and a plasmid • Plasmid and chromosomes are made of genes • Each gene makes one protein • - e.g enzyme • Cell activity depends upon chromosomes • BUT new genes can be added to the plasmid • Reprogrammed cell can express an inserted gene e.ginsulin

  3. Genetic Engineering v Selective Breeding • Both can alter the genetic makeup of a species for scientific benefit • Selective Breeding • Requires years of careful selection & breeding • Doesn’t always produce the ideal organism • Only animals that would normally produce the required product can be used

  4. Genetic Engineering v Selective Breeding • Genetic Engineering • Allows scientists to directly alter the genotype of a species • - suited to mankind’s needs • Species can be programmed to make products previously only made by another species • Much easier & cheaper to mass produce bacteria cells (than other species) • Mass quantities of a useful product e.g insulin can be produced

  5. Applications of Genetic Engineering • Medical – insulin, growth hormone, factor VIII • Commercial - • - Bacterial enzymes in detergents to digest stains • - Bacteria produce antifreeze (ethylene glycol) • - Yeast for beer making • - can be modified to produce more alcohol, but fewer carbs • - Cheese making: • - rennin curdles milk (rennin from calves stomach) • - rennin now produced by yeast cells

  6. Transgenic multicellular organisms • Genetic engineering on more complex organisms • Agrobacterium tumefaciens • - bacterium injects a plasmid into plant tissue • - ‘natural genetic engineer’ • Genetic material from plasmid is incorporated into the plants DNA. • Plant expresses bacterial genes • Scientists have altered the plasmids to insert useful genes into the plant DNA • These are Transgenic plants

  7. Transgenic Plants • Plants that have gained new genetic material from foreign DNA • Benefits to plants have included: • - extended shelf life in apples & tomatoes • - resistance to weedkiller in soya crops • - pea plants that produce their own insecticide

  8. Transgenic organisms - future • Cereals : crops will be modified to contain genes for certain characteristics • e.g resistance to herbicides, drought, pests, micro-organisms & salinity • - increased photosynthetic rate • Future - animal genes into plants e.g already haemoglobin grown in tobacco plants

More Related