Genetic Engineering Chapter 13 Selective Breeding Choosing the BEST traits for breeding. Most domesticated animals are products of SB. Also known as:

Genetic Engineering

Chapter 13

Selective Breeding

• Choosing the BEST traits for breeding.

• Most domesticated animals are products of SB.

• Also known as: Artificial Selection

• Techniques used in SB:

1. Hybridization

2. Inbreeding

HORSES

• Crossing dissimilar individuals to bring together the best traits of both organisms

• Produces hybrids

• * Hybrids can be different species crossed together or different types within the same species.

Hybridization

Golden Doodle and Puggle

Designer breeds or mutts?

Can you think of other fruit or

vegetable hybrids?

PluotBroccoflower

Inbreeding Domesticated animals and plants are inbred to develop

“breeds” and “varieties.” Researchers use inbred strains to assure genetic

similarities in their experiments. Problems: it can increase the chance of unfavorable

traits showing up. Golden retrievers - epilepsy Dalmations - hereditary deafness

Increasing Variation

Breeders can increase variation in a population by inducing mutations   Mutation = any change in DNA    

Mutations can happen randomly, as in this Scottish fold cat. Cat enthusiasts bred these cats from a single cat with a mutation for the ears.

A new strain of Oil-eating bacteria was produced.

Mutations can produce new kinds of plantsEx: Plants can sustain multiple sets of

chromosomes - Polyploidy. 

Manipulating DNA• Making any changes in the DNA code is:

Genetic Engineering

How DNA is Manipulated:• Extract DNA from cells• Cut DNA into smaller pieces (Restriction

enzymes)• Identify the sequence of bases in a DNA

molecule (Gel electrophoresis)• Make unlimited copies of DNA strands(PCR)• Combining different strands of DNA from

different organisms (recombinant DNA)

Transgenic Organisms

Definition: Organisms that contain genes from another organism.

Transgenic microorganisms – bacteria that produce human insulin.

Transgenic plants – major part of US agriculture; weed resistance; insecticides

Transgenic animals – growth hormones in livestock, resistance to bacterial infections, production of human proteins.

Transgenic animalsGene causes these mice to glow in the dark. Normally, the gene is found in jellyfish.

Transgenic plants: GM crops!

Putting bacteria to work for us. Using recombinant DNA The human Insulin gene

is inserted into the bacterial DNA.

The bacteria now produces human insulin at a much faster pace and cheaper than animals can.

Cloning

Natural clones – identical twins DNA must be identical to be a clone. Lifespan usually shortened. Health problems multiplied. Chance of survival before birth low. 1997  Dolly the sheep cloned, 1st

mammal

A donor cell is taken from a sheep’s udder. Donor

Nucleus

These two cells are fused using an electric shock.

Fused Cell

The fused cell begins dividing normally.

Embryo

The embryo is placed in the uterus of a foster mother.Foster

Mother

The embryo develops normally into a lamb—Dolly

Cloned Lamb

Egg Cell

An egg cell is taken from an adult female sheep.

The nucleus of the egg cell is removed.

Section 13-4

Figure 13-13 Cloning of the First Mammal