* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Document
Survey
Document related concepts
Behavioural genetics wikipedia , lookup
Medical genetics wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Genetic engineering wikipedia , lookup
Heritability of IQ wikipedia , lookup
Population genetics wikipedia , lookup
History of genetic engineering wikipedia , lookup
Genetic drift wikipedia , lookup
Designer baby wikipedia , lookup
Life history theory wikipedia , lookup
Microevolution wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Transcript
What is Genetics? Genetics is the scientific study of heredity What is a Trait? A trait is a specific characteristic that varies from one individual to another. Examples: Brown hair, blue eyes, tall, curly What is an Allele? Alleles are the different possibilities for a given trait. Every trait has at least two alleles (one from the mother and one from the father) Example: Eye color – Brown, blue, green, hazel Examples of Alleles: A = Brown Eyes a = Blue Eyes B = Green Eyes b = Hazel Eyes What are Genes? Genes are the sequence of DNA that codes for a protein and thus determines a trait. Gregor Mendel Father of Genetics 1st important studies of heredity Identified specific traits in the garden pea and studied them from one generation to another Dominant vs. Recessive Dominant - Masks the other trait; the trait that shows if present Represented by a capital letter R Recessive – An organism with a recessive allele for a particular trait will only exhibit that trait when the dominant allele is not present; Will only show if both alleles are present Represented by a lower case letter r Dominant & Recessive Practice T – straight hair t - curly hair TT - Represent offspring with straight hair Tt - Represent offspring with straight hair tt - Represents offspring with curly hair Genotype vs. Phenotype Genotype – The genetic makeup of an organism; The gene (or allele) combination an organism has. Example: Tt, ss, GG, Ww Phenotype – The physical characteristics of an organism; The way an organism looks Example: Curly hair, straight hair, blue eyes, tall, green Homozygous vs. Heterozygous Homozygous – Term used to refer to an organism that has two identical alleles for a particular trait (TT or tt) Heterozygous - Term used to refer to an organism that has two different alleles for the same trait (Tt) RR rr Rr Punnett Squares Punnett Square – Diagram showing the gene combinations that might result from a genetic cross Used to calculate the probability of inheriting a particular trait Probability – The chance that a given event will occur Punnett Square Parent Parent Offspring How to Complete a Punnett Square You Try It Now! Give the genotype and phenotype for the following cross: TT x tt (T = Tall and t = Short) TT x tt Step One: Set Up Punnett Square (put one parent on the top and the other along the side) T t t T TT x tt Step Two: Complete the Punnett Square T T t Tt Tt t Tt Tt TT x tt Step Three: Write the genotype and phenotype T T t Tt Tt t Tt Tt Remember: Each box is 25% Genotype: 4 - Tt Phenotype: 100% Tall You Try It Now! Give the genotype and phenotype for the following cross: Tt x tt Tt x tt Step One: Set Up Punnett Square (put one parent on the top and the other along the side) T t t t Tt x tt Step Two: Complete the Punnett Square T t t Tt tt t Tt tt Tt x tt Step Two: Complete the Punnett Square T t t Tt tt t Tt tt Remember: Each box is 25% Genotype: Tt - 2 (50%) tt - 2 (50%) Phenotype: 50% Tall 50% Short