exploring mendelian genetics
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
CHAPTER 11 SECTION 3SC B-46: PREDICT INHERITED
TRAITS BY USING THE PRINCIPLES OF MENDELIAN GENETICS
(INCLUDING SEGREGATION, INDEPENDENT ASSORTMENT, AND
TYPES OF DOMINANCE)
Exploring Mendelian Genetics
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?
F1 Generation allowed to self-pollinate
Results:
Mendel’s plants produced 556 seedsround & yellow: 315wrinkled & green: 32combinations 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
1. Inheritance of biological characteristics is determined by individual units called genes. Genes are passed from parents to their offspring.
2. If there are 2 or more alleles of a gene for a single trait, some forms may be dominant & others recessive
3. In most sexually reproducing organisms, each individual has 2 copies of a single gene (1 from each parent) & they separate when gametes are formed
4. 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
Name that type of inheritance
Name that type of inheritance!