Genetic Variation

Vocabulary You Should Know: Dominant Recessive Homozygous Heterozygous Genotype Phenotype Monohybrid Cross (punnett squares) Bio book Chapter 11, pgs

Laws of Genetics Principle of Segregation – Genes (1 from each parent) are separated from each other when gametes form (meiosis). Principle of Independent Assortment - Alleles for different genes separate independently of one another when gametes form (meiosis). Principle of Dominance – Some alleles are dominant & others are recessive. These laws account for the variations in inherited characteristics. Bio book Chapter 11, pgs

Mendelian Genetics Review Gregor Mendel studied biological inheritance with ____ plants. ______ determine traits. Different forms of a gene: ______ The Principle of Dominance states that some alleles are _________& others are ________. The Principle of Segregation states that during gamete formation, ______ segregate from each other so that each gamete carries only a ______ copy of each ____. pea Genes alleles dominantrecessive alleles single gene

...There are Exceptions to Every Rule! Genetics is not as simple as just dominant or recessive Some alleles are neither dominant nor recessive Majority of genes have more than 2 alleles Many traits are controlled by more than 1 gene

2 traits combine to make a 3 rd trait. Where 1 allele is not completely dominant over another Ex: some flowers. Red + White = Pink Incomplete Dominance Bio book pg. 272

Both traits appear at the same time. Where both alleles of a gene contribute to the phenotype of the organism Ex: Speckled black & white chickens, roan colored horsesCodominance Bio book pg. 272

3 or more alleles of the same gene Ex: coat color in Labrador retrievers A/B/O/AB blood type Multiple Alleles Bio book pg. 273

Blood Type Multiple Alleles: A, B, AB, O Codominance: AB Bio book pg

Trait controlled by 2 or more genes Ex: Skin color Polygenic Traits Bio book pg. 273

Trait controlled by 2 or more genes Ex: Eye color Polygenic Traits Bio book pg. 273

Characteristics of any organism are determined not only by their inherited genes. Characteristics are determined by the interaction between the genes & the environment Genes provide a plan for development, but how that plan unfolds also depends on the environment Genetics & the Environment Soil Type Nutrition Sunlight Climate Drug Use Resources Injuries Surgery Medicines Temperature Hygiene Bio book pg. 274

Bio book pg. 341

Pedigree Chart Bio book pg