Genetic Technology Ch. 13

Selective Breeding Selecting the most desired traits to serve as parents of the next generation Used for plants and animals Ex: Cows in 1947 produced an average of 4,997 lbs of milk; in 1997, a cow produced an average of 16,915 lbs of milk per year.

Inbreeding Used to ensure that breeds consistently exhibit a trait and eliminate undesired traits. Mating of closely related individuals Can bring out harmful, recessive traits because of greater chance that related individuals may both carry recessive allele.

Hybrids Crosses of two different purebred individuals can produce bigger and better offspring Ex: plants that are disease resistant can be crossed with others to produce larger and more numerous fruit.

Determining Genotypes Must be careful selecting genotypes to ensure the undesired recessive trait is not present. Use test cross to determine genotypes Cross an unknown individual with an individual of known genotype (i.e. homozygous recessive) and observe the offspring phenotypes

Think, Pair, Share If you were not sure of your genotype and you have brown hair, what genotype individual would you need to perform a test cross with to determine your genotype? Draw a punnett square and determine what ratio of genotypes your offspring would have. If you did not have any blonde hair children, what does that mean your genotype must be?

Genetic Engineering Faster and more reliable method for increasing the frequency of specific alleles in a population. Involves cutting/cleaving DNA from one organism into small fragments and inserting them into a host organism of the same or different species. aka: recombinant DNA technology

Transgenic Organisms Plants and animals with functional recombinant DNA are transgenic organisms. Recombinant DNA inserted in a host organism’s chromosomes will be used as if it were its own DNA.

Applications of DNA Technology Recombinant bacteria break down pollutants (oil) into harmless products. Recombinant bacteria can produce human growth hormone to treat dwarfism, and insulin to treat diabetes. Transgenic animals are used to study human chromosomes so that scientists can learn how to treat diseases in humans. Recombinant bacteria used on crops can prevent frost damage. Plants have been genetically engineered to resist herbicides, produce internal pesticides, or increase their protein production.

Applications in Humans Diagnosis of genetic disorders may be made before birth. Gene therapy can insert normal genes into human cells to correct genetic disorders. DNA fingerprinting and DNA samples (blood, hair, skin, or fluids) can be used to convict criminals.

Gene Therapy