Genetics and Evolution

Evolution - Factors

• Factors influencing evolution

  • Mutation
  • Gene flow
  • Genetic drift
  • Natural selection
  • Non-random mating

• Mutation

  • Introduction of genetic variation
  • Can be beneficial, harmful, or neutral
  • Example: Sickle cell anemia

• Gene flow

  • Movement of genes from one population to another
  • Can increase genetic diversity
  • Example: Migration of birds

• Genetic drift

  • Random changes in gene frequency due to chance events
  • More pronounced in small populations
  • Example: Founder effect

• Natural selection

  • Differential survival and reproduction of individuals with certain traits
  • Leads to adaptation
  • Example: Peppered moth

• Non-random mating

  • Selection of mates based on certain traits
  • Can lead to sexual selection
  • Example: Peacock feathers selection

======" #11. Genetics and Evolution - Types of Evolution

• Divergent evolution
  • Species evolve from a common ancestor and become more different over time
  • Example: Darwin’s finches
• Convergent evolution
  • Unrelated species evolve similar traits due to similar environments
  • Example: Wings in bats and birds
• Coevolution
  • Two or more species evolve in response to each other
  • Example: Flowering plants and their pollinators
• Parallel evolution
  • Related species independently evolve similar traits
  • Example: Marsupials in Australia and placental mammals in other continents
• Adaptive radiation
  • Rapid diversification of a single ancestral species into multiple new species
  • Example: Galapagos finches

#12. Genetics and Evolution - Speciation

• Speciation
  • Formation of new species from an existing species
• Allopatric speciation
  • Geographic isolation leads to speciation
  • Example: Islands and mainland populations
• Sympatric speciation
  • Speciation occurs without geographic isolation
  • Example: Polyploidy in plants
• Reproductive isolation
  • Barriers prevent members of different species from mating
  • Example: Temporal isolation
• Types of reproductive isolation
  • Prezygotic barriers
    • Temporal, ecological, behavioral, mechanical, and gametic barriers
  • Postzygotic barriers
    • Reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown

#13. Genetics and Evolution - Hardy-Weinberg Principle

• Hardy-Weinberg principle
  • Describes the genetic equilibrium in a population that is not evolving
• Conditions for Hardy-Weinberg equilibrium
  • Large population size
  • No migration
  • No mutation
  • Random mating
  • No natural selection
• Hardy-Weinberg equation
  • p^2 + 2pq + q^2 = 1
• Application of the Hardy-Weinberg principle
  • Estimating allele frequencies
  • Determining if the population is evolving

#14. Genetics and Evolution - Genetic Variation

• Genetic variation
  • Differences in the genetic makeup of individuals in a population
• Causes of genetic variation
  • Mutation
  • Recombination through sexual reproduction
• Importance of genetic variation
  • Provides raw material for evolution
  • Increases the chances of survival of a population in changing environments
• Sources of genetic variation
  • Sexual reproduction
  • Gene flow
  • Mutation

#15. Genetics and Evolution - Human Evolution

• Human evolution
  • Studying the evolutionary history of humans and our ancestors
• Homo sapiens
  • Modern humans belong to the species Homo sapiens
• Hominins
  • Group of species including modern humans and our close relatives
  • Examples: Homo neanderthalensis, Homo erectus
• Origins of humans
  • African hypothesis suggests humans evolved in Africa and migrated to other continents
• Fossil evidence
  • Fossils provide evidence of our evolutionary history
  • Example: Lucy, a famous Australopithecus afarensis fossil

#16. Genetics and Evolution - Genetic Disorders

• Genetic disorders
  • Diseases caused by abnormalities in an individual’s DNA
• Types of genetic disorders
  • Single gene disorders
    • Caused by mutations in a single gene
    • Example: Cystic fibrosis
  • Chromosomal disorders
    • Caused by changes in the number or structure of chromosomes
    • Example: Down syndrome
  • Multifactorial disorders
    • Caused by a combination of genetic and environmental factors
    • Example: Heart disease, diabetes
  • Mitochondrial disorders
    • Caused by mutations in the mitochondrial DNA
    • Example: Mitochondrial encephalomyopathy

#17. Genetics and Evolution - Genetic Engineering

• Genetic engineering
  • Manipulating an organism’s DNA to produce desired traits
• Steps in genetic engineering
  • Isolation of the target gene
  • Insertion of the gene into a vector
  • Transformation of the host organism
  • Selection and characterization of transformed organisms
• Applications of genetic engineering
  • Crop improvement through genetic modification
  • Production of recombinant proteins
  • Gene therapy for treating genetic disorders
  • Creating genetically modified organisms (GMOs)

#18. Genetics and Evolution - Cloning

• Cloning
  • Production of genetically identical copies of an organism
• Types of cloning
  • Reproductive cloning
    • Produces a clone of an entire organism
    • Example: Dolly the sheep
  • Therapeutic cloning
    • Produces embryonic stem cells for medical research
    • Does not result in the birth of a cloned organism
• Ethics of cloning
  • Cloning raises ethical concerns about the manipulation of life
  • Regulation is necessary to ensure responsible use of cloning technology

#19. Genetics and Evolution - Gene Therapy

• Gene therapy
  • Treating genetic disorders by introducing functional genes into damaged cells
• Types of gene therapy
  • Somatic gene therapy
    • Targeting non-reproductive cells to treat the individual
    • Does not affect future generations
  • Germline gene therapy
    • Modifying reproductive cells or early embryos to pass on genetic changes to future generations
    • Not currently performed in humans due to ethical concerns
• Challenges in gene therapy
  • Efficient and targeted delivery of genes
  • Long-term expression of the inserted genes
  • Potential risks and side effects

#20. Genetics and Evolution - Genetic Testing

• Genetic testing
  • Analyzing an individual’s DNA to detect genetic abnormalities or assess disease risk
• Types of genetic testing
  • Diagnostic testing
    • Identifying the genetic cause of a disease in an individual
  • Carrier testing
    • Assessing the risk of passing on a genetic disorder to offspring
  • Predictive testing
    • Identifying the risk of developing a disease in the future
  • Prenatal testing
    • Detecting genetic abnormalities in a fetus during pregnancy
• Benefits and limitations of genetic testing
  • Provides valuable information for medical intervention and family planning
  • Some genetic tests have limitations in accuracy and interpretation #21. Genetics and Evolution - Genetic Disorders and Inheritance Patterns
• Inheritance patterns of genetic disorders
  • Autosomal dominant
    • Disorders caused by a dominant allele on an autosomal chromosome
    • Example: Huntington’s disease
  • Autosomal recessive
    • Disorders caused by two recessive alleles on an autosomal chromosome
    • Example: Cystic fibrosis
  • X-linked recessive
    • Disorders caused by a recessive allele on the X chromosome
    • Example: Hemophilia
  • X-linked dominant
    • Disorders caused by a dominant allele on the X chromosome
    • Example: Vitamin D-resistant rickets
  • Y-linked
    • Disorders caused by mutations on the Y chromosome
    • Example: Male infertility

#22. Genetics and Evolution - Sex Determination

• Sex determination in humans
  • XX for females, XY for males
• Sex-linked traits
  • Traits controlled by genes on the sex chromosomes
• Example: Color blindness, hemophilia

#23. Genetics and Evolution - Genetic Polymorphisms

• Genetic polymorphisms
  • Variations in DNA sequence that occur at a frequency greater than 1% in a population
• Single nucleotide polymorphisms (SNPs)
  • Single base pair changes in DNA sequence
• Copy number variations (CNVs)
  • Changes in the number of copies of a particular DNA segment
• Insertions, deletions, and inversions
  • Structural variations in DNA sequence
• Importance of genetic polymorphisms
  • Can be used as markers for genetic mapping and studies of human evolution
  • Some polymorphisms have functional implications, affecting phenotype and disease risk

#24. Genetics and Evolution - Genetic Engineering Techniques

• Genetic engineering techniques
  • Polymerase chain reaction (PCR)
    • Amplification of specific DNA fragments
  • DNA sequencing
    • Determining the order of nucleotide bases in a DNA molecule
  • Restriction enzymes
    • Cutting DNA at specific recognition sites
  • Gel electrophoresis
    • Separation of DNA fragments based on size
  • Recombinant DNA technology
    • Joining of DNA from different sources

#25. Genetics and Evolution - Human Genome Project

• Human Genome Project (HGP)
  • International scientific research project to sequence and map the entire human genome
• Goals of the HGP
  • Determine the sequence of nucleotide base pairs in human DNA
  • Identify and map all genes in the genome
• Implications of the HGP
  • Advancements in personalized medicine
  • Understanding genetic basis of diseases
  • Ethical and legal considerations

#26. Genetics and Evolution - DNA Fingerprinting

• DNA fingerprinting
  • Analyzing genetic material to identify individuals
• Steps in DNA fingerprinting
  • DNA extraction from a sample
  • Amplification of specific DNA regions using PCR
  • Separation of DNA fragments by gel electrophoresis
  • Comparison of DNA banding patterns
• Applications of DNA fingerprinting
  • Forensic investigations
  • Paternity and maternity testing
  • Identification of human remains
  • Wildlife conservation

#27. Genetics and Evolution - Conservation Genetics

• Conservation genetics
  • Application of genetic methods to study and protect threatened species
• Genetic factors influencing conservation
  • Genetic diversity
  • Inbreeding
  • Genetic drift
• Techniques in conservation genetics
  • DNA barcoding
  • Population genetics analysis
• Conservation genetics in action
  • Determining population size and structure
  • Identifying source populations for translocations
  • Assessing risks of inbreeding and genetic disease

#28. Genetics and Evolution - Epigenetics

• Epigenetics
  • Study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence
• Epigenetic mechanisms
  • DNA methylation
  • Histone modifications
  • Non-coding RNAs
• Implications of epigenetics
  • Influence on development, aging, and disease
  • Role in understanding phenotypic variation and heritability
  • Potential for epigenetic therapies

#29. Genetics and Evolution - Stem Cells

• Stem cells
  • Undifferentiated cells capable of self-renewal and differentiation into specialized cell types
• Types of stem cells
  • Embryonic stem cells
  • Adult stem cells
    • Hematopoietic stem cells
    • Mesenchymal stem cells
• Applications of stem cells
  • Regenerative medicine
  • Disease modeling
  • Drug testing
  • Ethical considerations

#30. Genetics and Evolution - Gene Regulation

• Gene regulation
  • Processes that control the expression of genes
• Regulation of gene expression
  • Transcriptional regulation
  • Post-transcriptional regulation
  • Translational regulation
  • Post-translational regulation
• Importance of gene regulation
  • Ensures proper development and function of organisms
  • Enables cells to respond to environmental cues
  • Dysregulation can lead to diseases like cancer