Fundamentals of Genetics Gregor Mendel Genetics Pioneer Genetics
- Slides: 5
Fundamentals of Genetics Gregor Mendel: Genetics Pioneer • Genetics = study of _____. genes • Gregor Mendel – Australian Monk • Identified 7 pairs of contrasting characteristics pea _____. plants in _______ Mendel’s Experiment • Developed pure strains for each of the 14 characteristics by self pollination (pollen from anther to stigma of same flower or plant) • Then, cross pollinated • Parent plants = P 1 generation • First generation of offspring = F 1 generation F 2 generation • Second generation of offspring = ____ Mendel’s Results P 1: green pods x yellow pods -----> all green pods (F 1) F 1: green pods x green pods -------> ¾ green pods, ¼ yellow pods • Mendel got the same ¾ to ¼ ratio or each ____ pair of pure traits he tested
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Genes and Appearance Genotype: gene combination present Example: TT, Tt, tt Phenotype: Physical _______ appearance _____ due to gene action Example: tall, short Homozygous: both gene of pair chromosomes _______ Example: TT, tt Heterozygous: genes of pair _______ chromosomes Example: Tt Also called a hybrid Alleles: contrasting traits for the same characteristic Example: tallness and shortness Multiple Alleles: traits with more than two alleles Example: blood type (A, B, O) 2 (two) How many of these possible different genes can you inherit? _________
Mendel’s Conclusions Principles of Dominance and Recessiveness expression = one factor in a pair may mask the other, preventing its _______. Law of Segregation = a pair of factors is segregated, or separated during the formation of gametes Law of Independent Assortment = factors are distributed to gametes separate of other factors *Later found to be untrue where gene linkage is present Modern Look at Mendel’s Work genes • Mendel’s factors = _______. • Letters used to represent gene pairs: – Capital letters for dominant genes – Lower case letters for recessive _____ genes Example: Tallness vs. Shortness T = tall gene t = short gene Tall TT = _____ Tall Tt = _____ tt =Short ____
