Genetic Variation and its Sources

Study Notes

Genetic Variation

Sources of Genetic Variation:
- Mutation: changes in DNA sequence
- Genetic recombination: crossing over and independent assortment during meiosis
- Gene flow: movement of genes between populations
- Genetic drift: random changes in allele frequency
Types of Genetic Variation:
- Cytogenic variation: changes in chromosome number or structure
- Molecular variation: changes in DNA sequence
Consequences of Genetic Variation:
- Increased fitness and adaptation to environment
- Evolution of new species
- Disease and disorder susceptibility

Cell Biology

Cell Structure:
- Plasma membrane: semi-permeable membrane separating cell from environment
- Cytoplasm: jelly-like substance inside cell membrane
- Nucleus: contains genetic material (DNA)
- Mitochondria: site of cellular respiration
- Endoplasmic reticulum (ER): involved in protein synthesis and transport
- Ribosomes: site of protein synthesis
Cellular Transport:
- Passive transport: movement of molecules from high to low concentration
  - Diffusion
  - Osmosis
- Active transport: movement of molecules from low to high concentration
  - Requires energy input

Speciation

Definition: process by which a new species emerges from an existing one
Mechanisms of Speciation:
- Geographic isolation: physical barrier separating populations
- Reproductive isolation: inability of populations to interbreed
- Ecological isolation: adaptations to different environments
Types of Speciation:
- Allopatric speciation: speciation due to geographic isolation
- Sympatric speciation: speciation within same geographic area
Evidence for Speciation:
- Morphological differences: distinct physical characteristics
- Reproductive barriers: inability to produce fertile offspring

Genetic Variation

Mutation: changes in DNA sequence, resulting in new alleles
Genetic recombination: crossing over and independent assortment during meiosis, increasing genetic diversity
Gene flow: movement of genes between populations, altering allele frequency
Genetic drift: random changes in allele frequency, leading to loss or fixation of alleles
Cytogenic variation: changes in chromosome number or structure, affecting gene expression
Molecular variation: changes in DNA sequence, altering gene function
Consequences of genetic variation: increased fitness and adaptation to environment, evolution of new species, and disease and disorder susceptibility

Cell Biology

Plasma membrane: semi-permeable membrane separating cell from environment, regulating material transport
Cytoplasm: jelly-like substance inside cell membrane, providing mechanical support and medium for metabolic reactions
Nucleus: contains genetic material (DNA), regulating gene expression and cell growth
Mitochondria: site of cellular respiration, generating energy for cell
Endoplasmic reticulum (ER): involved in protein synthesis, transport, and modification
Ribosomes: site of protein synthesis, translating mRNA into polypeptides
Passive transport: movement of molecules from high to low concentration, including diffusion and osmosis
Active transport: movement of molecules from low to high concentration, requiring energy input

Speciation

Definition: process by which a new species emerges from an existing one, resulting in reproductive isolation
Geographic isolation: physical barrier separating populations, leading to allopatric speciation
Reproductive isolation: inability of populations to interbreed, due to genetic or behavioral differences
Ecological isolation: adaptations to different environments, reducing gene flow
Allopatric speciation: speciation due to geographic isolation, resulting in distinct species
Sympatric speciation: speciation within same geographic area, often due to ecological isolation
Evidence for speciation: morphological differences, reproductive barriers, and genetic differences

Description

Understand the different sources of genetic variation, including mutation, genetic recombination, gene flow, and genetic drift. Learn about the types of genetic variation and their consequences on fitness.