Chapter 10 Patterns of Inheritance Concept 10 1

Chapter 10: Patterns of Inheritance

Concept 10. 1 Genetics Developed from curiosity about inheritance…

Vocab • Trait • Genetics • Cross Fertilization

Blending Theory • • Early 1800’s Blue x Red = Purple always produce purple Problems with theory…

Gregor Mendel • • • Austrian Monk Taught High School Biology Mathematician Lived in a Monestary Bred Pea Plants in Garden Crossed generations for 7 years

Mendel’s Theory • Particulate Hypothesis – True-breeding – Led to “Genetics” • Used self- vs. cross-fertilization

Concept 10. 2 Mendel discovered that inheritance follows rules of chance…

Vocab • • Hybrids Monohybrid cross Allelese Homozygous Heterozygous Dominant Recessive • • • Phenotype Genotype Testcross Dihybrid cross Principle of Segregation • Principle of Independent Assortment • Generations

Principle of Segregation • True breeding=pure (homozygous) • True x true = hybrid

Pea Traits: • • • Allele= purple vs. white Dominant= Capital (B) Recessive= Lowercase (b) Homozygous= BB or bb Heterozygous = Bb

Principle of Segregation • Alleles separate into different gametes during meiosis…

Probability • The mathematical prediction that a specific event will occur! • Written as fractions, decimals, or percents!

Genotype vs. Phenotype • Genotype= Gene Combination (BB, Bb, or bb) • Phenotype= What it looks like (Black vs. Fawn)

Testcross: • Cross between one known parent and one unknown parent to determine the genotype of the unknown.

10. 4 Meiosis Explains Mendel

Chromosome Theory of Inheritance • Genes are located on chromosomes • Chromosome behavior accounts for inheritance • Chromosomes undergo segregation and independent assortment

Reminder…Karyotype

Gene Locus • Each gene has a specific location on each chromsome

Genetic Linkage • Same chromosome = genes linked – Unless crossing over occurs • Blue eyes paired with blonde hair • Brown eyes paired with brown hair

10. 5 Sex-linked traits have unique inheritance patterns…

Sex Linked Genes • A gene that is located on the sex chromosome • Discovered by Thomas Hunt Morgan – Studied eye color in fruit flies • Result in unusual inheritance ratios (patterns)

Sex-Linked Disorders • Red-green color blindness, hemophilia, male pattern baldness, etc. • Recessive traits more common in men! – Usually allele is absent on the y chromosome