Selective Breeding and Natural Selection

DNA Technology

Genetic engineering is the field of science that deals with making changes in an organism’s DNA

DNA extraction the process of separating DNA from the rest of the cell

Restriction enzymes are used to cut DNA. They are very specific and cut DNA only in specified places due to a nucleotide sequence.

Gel electrophoresis procedure where DNA fragments are placed in a special gel and an electric current is run through it. The current picks up the pieces and carries them through the gel. Bands are then compared to a known sample. This is used to compare samples from crime scenes to suspects(looking for a specific match), or a child to a possible family or father(looking for similarities in DNA). CODIS is the genetic “bank” of DNA samples from crime scenes.

DNA fingerprinting an analysis of sections of DNA that are used to identify individuals….such as criminals, missing children, MIA soldiers, crime victims, etc. Each person has unique DNA that can be used for identification.

Suspect 3 has some explaining to do…

Ways to get desired traits Selective Breeding – Inbreeding – hybridization Cloning Genetic engineering

Selective breeding allowing only those animals or plants with desired traits to reproduce. This is how we have developed many varieties of corn, wheat, rice, cows, horses, dogs, etc. These are referred to as domesticated varieties.

Selective Breeding Selective breeding has been practiced for thousands of years. It involves humans choosing two individuals to mate to produce offspring with certain desirable characteristics, – such as leaner meat on an animal or wheat seeds that remain attached to the plant for longer. – Many plants and animals for domestic and agricultural purposes have been bred in this way to produce new varieties.

Dogs are a great example

Examples Cattle and sheep have been specifically bred for such things as leaner meat, more milk, creamier milk, better quality wool and increased resistance to disease. Pigs, due to selective breeding are less aggressive, have smaller tusks and more meat compared to their genetically similar ancestors.

Examples Horses have been selectively bred from wild horses over centuries resulting in many varieties including draft horses. – breeds such as the Shire, Clydesdale, Belgian and Suffolk which are used for specific farming purposes, but all involve greater strength, size and ability to pull wagons, ploughs and drays. – Race horses also originated from wild horses and have been bred for greater speed.

Forms of selective breeding 1.Inbreeding- involves crossing 2 individuals that have similar desired traits. – The offspring will probably have the same traits. – Increases the chances of the recessive alleles being inherited – Lead to genetic disorders

Forms of selective breeding 2. Hybridization- crossing 2 genetically different individuals (hybrid-different) - have best traits from both parents

Hybridization the crossing of dissimilar organisms to bring together the best of both organisms. Many crops and domesticated animals are hybrids

Cloning Producing offspring with desired traits that are genetically identical to the parent. – Cutting from a plant to grow new one – Dolly, a sheep produced in 1996 was the first cloned mammal. ng.htm

Cloning refers to transferring the genetic material of one cell into another cell..this can result in either a group of identical cells or a new individual, in which case it is called reproductive cloning. Dolly, a sheep produced in 1996 was the first cloned mammal.

Make MIMI the Mouse nt/tech/cloning/clickandclone/

Recombinant DNA the combination of DNA from different sources. (EX> Human gene for human growth hormone is inserted into bacteria and then used to produce growth hormone used to treat growth disorders). This is the same procedure used to produce insulin for diabetics, or clotting factor for hemophiliacs: they just insert a different gene into the bacteria.

Genetic Engineering

G M term used to describe genetically modified foods

Gene therapy a process in which an absent or faulty gene is replaced with a normal working gene. This has been successfully done in some cases in humans

Gene therapy Using genetic engineering to correct some genetic disorders in humans. Involves inserting copies of a gene directly into a person’s cells. – Hemophilia- replaces the defective allele on the X chromosome to correct the instructions for blood clotting.

Vocabulary Selective Breeding: The intentional breeding of organisms with desirable traits in an attempt to produce offspring with similar desirable characteristics or with improved traits. Species: A group of organisms having common characteristics that is capable of mating with one another. Variation: Differences in individual living things from each other. gene: A segment of DNA that codes for a particular protein. gene pool: All the genes of all the members in a population.

selective pressure: Any environmental factor that favors one trait over another. mutation: A random change in a gene or a group of genes. genetic isolation: What occurs when two groups of one species are prevented from breeding with each other. inherited trait: An inherited characteristic—such as hair and eye color or muscle and bone structure—that has been passed on from a previous generation. acquired trait: An acquired characteristic—such as the ability to ride a bike or do karate—that is attained throughout life. Acquired traits are not passed on genetically.