Genetic Technology Applied Genetics

Genetics and Biotechnology Selective Breeding For thousands of years humans have selected plants and animals with certain qualities The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding. Still use this today Tomatoe plants, corn, cows Saint Bernard Rescue dog Husky Sled dog German shepherd Service dog

Ex’s of Selective Breeding Farmers select seeds from largest heads of grain, juiciest berries, most disease-resistant clover Farmers raise cows from best milk producers, save eggs of best egg- laying hens 1947- average cow produced 4997 pounds of milk/year 1997- average cow produced 16 915 pounds of milk/year 2017- average cow produced 22 774 pounds of milk/year!!! What farmers do is actually selectively breeding or artificial selection for desired traits. This results in increasing the frequency of a desired allele within a population

Inbreeding develops pure lines Inbreeding is: the process in which two closely related organisms are bred to have the desired traits and to eliminate the undesired ones in future generations Pure breeds are maintained by inbreeding. A disadvantage of inbreeding is that harmful recessive traits also can be passed on to future generations Examples: dogs and horses

Hybrids are usually bigger and better Selective breeding of plants can increase productivit of food for humans Ex. disease resistant plant crossed with other plant that produces larger sized fruit. Result will be plant that will be disease resistant AND produce large fruit *Hybrid= offspring of parents that have different forms of a trait Wheat, corn, rice, garden flowers ex of hybridized plants

Determining Genotype In order to artifically select the the ‘best’ parents, we need to choose the correct parents to cross, with the desired genotype Genotype for homozygous recessive, because phenotype is obvious, easy to determine Homozygous or heterozygous dominant can be difficult to determine

Genetics and Biotechnology Test Cross A test cross involves breeding an organism that has the unknown genotype with one that is homozygous recessive for the desired trait.

In this test cross of Alaskan malamutes, the known test dog is homozygous recessive for the dwarf allele (dd)and the other dog’s genotype is unknown