Applied Genetics Selective Breeding and Genetic Engineering

Selective Breeding = crossing of plants or animals that have desirable traits to produce offspring with those traits Increased strength Leaner meat (less fat) Disease resistance Larger grain/fruit Better taste

hybridization = crossing two organisms (same genus/species, “kind”) with variations of particular trait(s) to produce offspring with a mixture of the trait(s)

Offspring inherits traits of both parents Donkey X horse = mule Modern grains – corn, wheat Ancient wild wheat X wild goat grass = nutritious hybrid wheat used for bread

The greater the difference between “kinds” (genus/species) being hybridized, the more likely the hybrid will be sterile

Hybridization McIntosh X Red Delicious = Empire

Inbreeding = crossing 2 organisms that have the same or similar trait(s) to produce animals with the same trait(s) Idea is to preserve the desirable traits

Organisms are genetically similar and can lead to negative consequences: Increased chances of inheriting disorders Increased chances of contracting certain diseases Decreased ability to adapt to environmental changes

Interesting Hybrids liger = cross between lion (father) and tiger (mother)

Interesting Hybrids Tiglon = cross between male tiger and female lion

Beefalo/cattalo = bison x cow

Hinny Female donkey x male horse

Cama = male camel x female llama

Cloning A clone is an organism that has the exact same genes as the organism from which it was produced. African violet Sheep Pigs

Genetic Engineering Process in which genes (sections of DNA) are taken from one organism and transferred to another

Recombinant DNA Section of DNA is separated from strand of one organism This is spliced into the DNA of another organism DNA is now combined Modified DNA will cause cells to carryout processes in a different way

Products resulting from genetic engineering Medicine Insulin, human growth hormone (produced by altered bacteria) Hepatitis B vaccine (produced by altered yeast cells)

Potential problems Cross-pollination of GM crops to wild varieties can cause weeds to become herbicide resistant Insects may become quickly resistant to insecticides because of exposure to GM crops

Predators that eat insects who have eaten GM crops can be affected in unknown ways People who eat GM crops can be affected in unknown ways Toxic effects Allergic reactions Resistance to antibiotics

Warnings Genes are now known to control more than one trait By altering/changing a single gene, multiple traits may be changed in ways we can’t predict Human genes are only a small percentage of the information contained in DNA (5% or less)…we don’t know what most of the rest does

The Future…. Chimera – organism or component composed of different genetic material

So far… Pigs with human blood Mice with human brain cells Sheep with human tissues in hearts & livers Fusion of human & rabbit bio- matter produced chimeric embryos

Learning About Human Genetics A genome is all the DNA in one cell of an organism The Human Genome Project’s goal is to identify the DNA sequence of every gene in the human genome 20,000 to 25,000 genes Finding the exact location and function of each gene could take decades!

DNA Fingerprinting Hair, skin and blood can all be used to make a DNA fingerprint No 2 people have the exact same DNA A DNA finger print consists of a series of bands, something like a bar code. DNA finger prints can be used to show whether people are related, identify people and solve crimes.

Humans have only 300 more genes than what are also found in mice… “This tells me genes can’t possibly explain all of what makes us what we are.” Craig Venter, president of Celera Genomics (Maryland firm that led one of the mapping teams for the Human Genome Project)