Lesson 4: Basic Genetics PDF

Lesson 4: Basic Genetics ​ Gregor Mendel: Known as the father of genetics, he conducted experiments with pea plants to understand inheritance. ​ True-breeding: Organisms that consistently produce offspring with the same traits when self-pollinated. ​ Hybrid: Offspring resulting from...

Lesson 4: Basic Genetics ​ Gregor Mendel: Known as the father of genetics, he conducted experiments with pea plants to understand inheritance. ​ True-breeding: Organisms that consistently produce offspring with the same traits when self-pollinated. ​ Hybrid: Offspring resulting from the cross of two different true-breeding parents. ​ Monohybrid Cross: A genetic cross that examines the inheritance of a single trait. ​ Punnett Square: A diagram used to predict the genotype and phenotype ratios of offspring from a genetic cross. ​ Homozygous Dominant: Two dominant alleles (e.g., AA). ​ Heterozygous: One dominant and one recessive allele (e.g., Aa). ​ Homozygous Recessive: Two recessive alleles (e.g., aa). ​ Law of Segregation: During gamete formation, the two alleles for a gene segregate from each other. ​ Allele: Different forms of a gene (dominant or recessive). ​ Dominant vs. Recessive: Dominant alleles mask the effect of recessive alleles in heterozygotes. ​ Genotype vs. Phenotype: Genotype refers to the genetic makeup (e.g., Aa), while phenotype refers to the physical expression of a trait (e.g., brown eyes). Lesson 5: Advanced Genetics ​ Codominance: Both alleles in a heterozygote are fully expressed (e.g., AB blood type). ​ Incomplete Dominance: A blend of traits from both alleles (e.g., red and white flowers producing pink offspring). ​ Blood Types: Human blood types (A, B, AB, O) are determined by codominant alleles and involve multiple alleles (IA, IB, i). Lesson 6: Inheritance Patterns ​ Pedigree Chart: A diagram showing the inheritance of traits in a family over generations. ​ Autosomal Chromosomes: Non-sex chromosomes that can carry traits. ​ Autosomal Dominant/Recessive Inheritance: Dominant traits only require one copy of the allele to be expressed, while recessive traits require two. ​ Pedigree Problems: Analyzing family trees to determine inheritance patterns. Lesson 7: Sex-Linked Traits ​ X-linked Traits: Traits carried on the X chromosome; more common in males. ​ Y-linked Traits: Traits carried on the Y chromosome; passed from father to son.  ​ Genetic Disorders: Examples include hemophilia (X-linked recessive) and color blindness. Lesson 8: Multi-Trait Inheritance ​ Multi-trait Inheritance: Involves studying multiple traits simultaneously. ​ Dihybrid Cross: Examines the inheritance of two traits at once (e.g., AaBb x AaBb). ​ 4x4 Punnett Square: Used for dihybrid crosses to predict offspring ratios. ​ Law of Independent Assortment: Genes for different traits segregate independently during gamete formation. ​ Product Law: The probability of two independent events occurring together is the product of their individual probabilities. ​ Discontinuous vs. Continuous Variation: Discontinuous traits (e.g., flower color) show distinct categories, while continuous traits (e.g., height) show a range of phenotypes. Lesson 9: DNA and Mutations ​ DNA Structure: Composed of nucleotides, which include a sugar, phosphate group, and nitrogenous base. ​ Nitrogenous Bases: Adenine (A), Guanine (G), Thymine (T), Cytosine (C). A pairs with T, and G pairs with C. ​ Nucleotide: The basic building block of DNA. ​ Mutations: Changes in DNA sequence; can be point mutations (single nucleotide changes) or chromosomal mutations (large-scale changes). ​ Inheriting Mutations: Mutations can be passed on to offspring if they occur in germ cells. ​ Lactose Intolerance: A common condition where individuals lack the enzyme to digest lactose, often due to mutations. ​ Antibiotic Resistance in Bacteria: Occurs when mutations provide bacteria with the ability to survive antibiotic treatment, leading to the spread of resistant strains.