Mendels crosses Gregor Mendel (1822-1884) data analysis => - PDF document

Mendel’s scientific approach to the study of heredity Introduction to Human Genetics ● well characterized materials Module 1 Mendelian genetics ● accurate quantitive records Mendel’s crosses Gregor Mendel (1822-1884) ● data analysis => model Dr Ewa Piotrowska Department of Molecular Biology Mendel’s scientific approach to the study of heredity ● well characterized materials ● accurate quantitive records Gregor Mendel (1822-1884) ● data analysis => model Gregor Mendel (1822-1884)  P:  F 1 : 2.96:1 F 2 : 5,474 1,850 1

Mendel’s conclusions ● UNIT FACTORS IN PAIRS ● DOMINANCE / RECESSIVENESS ● SEGREGATION Homozygous Definitions  P: Having identical alleles for one or more genes. RR rr Dominant trait The trait expressed in the F 1 Gene (or heterozygous) condition. The fundamental unit of heredity and the basic structural and Recessive trait functional unit of genetics. The trait unexpressed in the F 1 but expresses in some members Phenotype of the F 2 generation  Heterozygous The observable properties F 1 : Carrying two different alleles of an organism. for one or more genes. Rr Rr Genotype The specific genetic Allele constitution of an organism. Segregation One of the possible alternative forms The separation of members of a gene of a gene, usually distinguished from pair from each other during gamete other alleles by its phenotypic effect. formation.  P: RR rr  F 1 : Studying the inheritance of Rr Rr Punnett two characters simultaneously square R r F 2 : R RR Rr r Rr rr 2

Variations on a Theme by Mendel ● incomplete dominance ● codominance ● multiple alleles ● epistasis 3