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Genetics •Heredity is the passing of traits from parent to offspring. Gregor Mendel - “Father of Genetics” The first to prove living things pass traits to their young. Video Mendel • Each gene or allele can be dominant or recessive. • Capital letter = dominant allele • Lower case letter = recessive allele. • A tool used to predict traits in genetics is a Punnett Square. Father’s Genes T t T = brown hair t Tt t t t Tt t t Mother’s Genes t = blonde hair Punnett Square :55 •The physical trait that shows is the phenotype. • The pair of alleles is the genotype. •An organism with 2 alleles that are the same is homozygous. •An organism that has two different alleles is heterozygous. G G g GG gG Punnett Square :55 Brain Pop G = Green Eyes g = Brown Eyes g Gg gg • 2 heterozygous offspring Gg, gG • 2 homozygous offspring GG, gg • Phenotype = 3 offspring with green eyes and 1 offspring with brown eyes. • Genotype = 1 GG 2 Gg 1 gg Incomplete Dominance – When the offspring of 2 homozygous parents show a different phenotype. R R W RW RW W RW RW R = red W = white Multiple Alleles – A trait that is controlled by more than two genes. A - dominant B - dominant O - recessive AO = A OO = O BO = B AB = AB Polygenic Inheritance – When a group of gene pairs act together to make a trait. Sex Determination Male XY 1. Determined through sex cells 2. Animation: Formation of twins Female XX Males determine the sex of the baby. Recessive Genetic Disorders Sickle-cell Anemia Cystic Fibrosis 1. Pedigrees Pedigrees A tool for tracing the occurrence of a trait in a family. Genetic engineering Genetic Engineering Biological and chemical methods to change the DNA that makes up a gene. There are 2 kinds of genetic engineering 1. Recombinant DNA Video: Recombinant DNA Made by inserting a useful segment of DNA from one organism into a bacterium. Video: Gene Therapy 2. Gene Therapy A) A normal gene is placed in a virus. B) It then delivers the normal gene when it infects its target cell. C) The normal gene replaces the defective one. Star @ 2:00 Selecting plants with the most desired traits to breed for the next generation is called selective breeding. Genetically Engineered Plants Pros Cons 1. Can grow bigger crops 1. Don’t know how food will affect our health 2. Better tasting 3. Add extra vitamins and minerals Who determines the sex of the baby? Man = XY Female = X X X Y X XX XY X XX XY