Ch. 15.1 Selective Breeding

1. Ch. 15.1 Selective Breeding

2. Selective Breeding • breeding of organisms to produce certain desired traits in their offspring. • http://www.youtube.com/watch?v=_ZbnfjLoDSY

3. Selective Breeding • The differences among breeds of dogs are great. Where did these differences come from? • Humans use selective breeding to produce animals with certain desired traits. Selective breeding allows only those animals with wanted characteristics to produce the next generation.

4. Hybridization • American botanist Luther Burbank developed more than 800 varieties of plants using selective breeding methods. • One method Burbank used was hybridization, crossing dissimilar individuals to bring together the best of both organisms. • Hybrids—the individuals produced by such crosses—are often hardier than either of the parents.

5. Inbreeding • To maintain desirable characteristics in a line of organisms, breeders often use inbreeding, the continued breeding of individuals with similar characteristics. • The many breeds of dogs are maintained using inbreeding, ensuring that the characteristics that make each breed unique are preserved.

6. Biotechnology • Application of a technological process, invention, or method to living organisms.

7. 15. 2 Recombinant DNA • It is relatively easy to extract DNA from cells and tissues. • The extracted DNA can be cut into fragments of manageable size using restriction enzymes. • These restriction fragments can then be separated according to size, using gel electrophoresis or another similar technique.

8. Copying DNA- Extracting DNA using Gel Electrophoresis

9. Finding Genes- Southern Blot Analysis

10. Polymerase Chain Reaction • Once biologists find a gene, a technique known as polymerase chain reaction (PCR) allows them to make many copies of it. • 1. A piece of DNA is heated, which separates its two strands.

11. Polymerase Chain Reaction • 2. At each end of the original piece of DNA, a biologist adds a short piece of DNA that complements a portion of the sequence. • These short pieces are known as primers because they prepare, or prime, a place for DNA polymerase to start working.

12. Polymerase Chain Reaction • 3. DNA polymerase copies the region between the primers. These copies then serve as templates to make more copies. • 4. In this way, just a few dozen cycles of replication can produce billions of copies of the DNA between the primers.

13. Genetic Engineering- any technique used to identify or change genes. • Examples: Corn, Tomato, Cows • Gel Electrophoresis- using electric currents to separate fragments or bases of DNA. • Gene Cloning- making an exact copy of a living organism. • Example- Dolly- first cloned mammal from a body cell.

14. Stem Cells- primitive cells that can be cultured into tissues or organs. • Examples: • Adult- umbilical cord • Embryonic- developing embryos • Human Genome Project- project to map every human chromosome.