160 likes | 319 Views
Exploring Mendelian Genetics. Chapter 11 Section 3 SC B-46: Predict inherited traits by using the principles of Mendelian genetics (including segregation, independent assortment, and types of dominance). Essential Question.
E N D
Exploring Mendelian Genetics Chapter 11 Section 3 SC B-46: Predict inherited traits by using the principles of Mendelian genetics (including segregation, independent assortment, and types of dominance)
Essential Question How would you explain the inheritance patterns beyond dominant & recessive?
Dihybrid Crosses Mendel also performed an experiment to follow 2 different genes as they passed from parents to offspring Mendel chose true-breeding round, yellow peas crossed with true-breeding wrinkled, green for F1 (RRYY) x (rryy) What genotype/phenotype will the offspring have?
Mendel’s 2nd Experiment The Inheritance of 2 Traits Does the inheritance of 1 characteristic influence the inheritance of another characteristic? For example: Does pea shape influence pea color?
Results: Mendel’s plants produced 556 seeds round & yellow: 315 wrinkled & green: 32 combinations of parent phenotypes: 209 Mendel’s conclusion: Alleles for seed shape & color segregate independently when gametes forming
Law of Independent Assortment Genes from different traits can segregate independently during the formation of gametes. This accounts for the many genetic variations observed in plants, animals, & other organisms
Summary of Mendel’s Principles Inheritance of biological characteristics is determined by individual units called genes. Genes are passed from parents to their offspring. If there are 2 or more alleles of a gene for a single trait, some forms may be dominant & others recessive In most sexually reproducing organisms, each individual has 2 copies of a single gene (1 from each parent) & they separate when gametes are formed Alleles for different genes usually separate independently of one another.
Incomplete Dominance Cases where neither allele is dominant the heterozygous individual will have a phenotype that is a blend of the 2 alleles.
Codominance Both alleles for a gene are expressed in the phenotype of a hybrid individual
Multiple Alleles genes that have >2 alleles
Polygenic Traits Traits controlled by the interactions of several genes
Genetics & the Environment Genes provide a plan for development but how that plan unfolds also depends on the environment