Genetics and Inheritance Patterns

Genetics and Traits

• Autosomal Traits: Genes located on chromosomes 1-22; affect both sexes equally.
• Sex-Linked Traits: Genes positioned on the X chromosome; usually affect males more significantly due to their single X chromosome.
• Codominance: Both alleles in a heterozygote are expressed equally, resulting in distinct phenotypes.
• Incomplete Dominance: Intermediate phenotype appears in heterozygotes, rather than full expression of one allele.
• Polygenic Traits: Influenced by multiple genes, exhibiting a spectrum of phenotypes (e.g., skin and eye color).

Analyzing Pedigrees

• Sex-Linked vs. Autosomal: Sex-linked traits show disproportionate effects on males; autosomal traits affect both sexes equally.
• Dominant vs. Recessive: Dominant traits appear in every generation, while recessive traits appear in offspring of carriers (unaffected parents).

DNA, RNA, and Protein Synthesis

• Central Dogma: DNA → RNA → Protein → Trait; proteins determine phenotype.
• DNA Composition: Consists of nucleotides A, T, C, and G; genes are DNA segments coding for proteins.
• RNA Composition: Made of nucleotides A, U, C, and G; transcribed from DNA.
• Transcription: Process where mRNA is synthesized from DNA; occurs in the nucleus with RNA polymerase as the main enzyme.

Exam Preparation

• Final Exam Structure: Approximately 75% of questions from Modules 8-15, 25% from Modules 1-6; comprises multiple-choice, true/false, and matching questions.
• Exam Duration: 1 hour and 15 minutes to answer around 70 questions, most students finish well under time.
• Permitted Materials: One hand-written 4x6 index card with notes; no other materials allowed.

Genetic Vocabulary

• Key terms include dominant, recessive, allele, homozygous, heterozygous, genotype, and phenotype.
• Carrier: Refers to heterozygous individuals that can pass on a recessive trait.

Patterns of Inheritance

• Understand outcomes of monohybrid crosses for autosomal dominant, recessive, and sex-linked traits through Punnett Squares.
• Genetic Variation: Caused by independent assortment during meiosis, crossing over, and random fertilization.

Evolutionary Concepts

• Divergent Evolution: Homologous structures evolve from a common ancestor; examples include vertebrate forelimbs.
• Convergent Evolution: Analogous structures develop due to similar environmental pressures; examples include shark/dolphin body forms.
• Evolutionary Forces: Mutation, natural selection, genetic drift (bottleneck and founder effects), and gene flow through migration.

Speciation and Species Concepts

• Biological Species Concept: Defines species as groups capable of interbreeding and producing fertile offspring.
• Genetic Divergence: Accumulation of genetic differences requiring reproductive isolation (prezygotic or postzygotic).
• Speciation Types: Allopatric (geographically isolated) versus sympatric (reproductive barriers without geographic isolation).

Domains of Life

• Domain Archaea: Single-celled prokaryotes, many extremophiles.
• Domain Bacteria: Single-celled prokaryotes commonly known as bacteria.
• Domain Eukarya: Eukaryotic organisms including protists, fungi, plants (multicellular), and animals (multicellular); characterized by complex cell structures.