Slide 1

Molecular Basis of Inheritance

• Genetics and Evolution
• Importance of understanding the molecular basis of inheritance
• Significance of radioactive Phosphorus and Sulfur in experiments

Slide 2

DNA and RNA

• DNA (Deoxyribonucleic acid)

  • Structure: double helix composed of nucleotides
  • Function: carries genetic information
  • Examples: chromosomes, genes

• RNA (Ribonucleic acid)

  • Structure: single-stranded nucleic acid molecule
  • Types of RNA: mRNA, tRNA, rRNA
  • Function: participates in protein synthesis

Slide 3

Nucleotides

• Composition of nucleotides:

  • Nitrogenous base (Adenine, Thymine, Cytosine, Guanine, Uracil)
  • Pentose sugar (deoxyribose in DNA, ribose in RNA)
  • Phosphate group

• Examples:

  • Adenine pairs with Thymine in DNA
  • Guanine pairs with Cytosine in DNA

Slide 4

DNA Replication

• Process by which DNA is copied during cell division

• Steps:

  1. DNA unwinding
  2. Separation of DNA strands
  3. Complementary base pairing
  4. Formation of new DNA strands

• Example: Watson and Crick model of DNA replication

Slide 5

Transcription

• Process of synthesizing RNA using DNA as a template

• Steps:

  1. Initiation
  2. Elongation
  3. Termination

• Example: mRNA synthesis from DNA template

Slide 6

Genetic Code

• Set of rules by which information in genetic material (DNA or mRNA) is translated into proteins
• Triplet code: each codon consists of three nucleotides
• Examples:
  • AUG: start codon
  • UAA, UAG, UGA: stop codons

Slide 7

Translation

• Process of protein synthesis using the genetic code

• Steps:

  1. Initiation
  2. Elongation
  3. Termination

• Examples: tRNA, ribosomes

Slide 8

Mutations

• Changes in DNA sequence

• Types of mutations:

  1. Point mutations (substitution, insertion, deletion)
  2. Frameshift mutations
  3. Chromosomal mutations (deletion, duplication, inversion, translocation)

• Examples: sickle cell anemia, Down syndrome

Slide 9

Recombinant DNA Technology

• Techniques used to manipulate DNA for various purposes

• Methods:

  1. Restriction enzymes
  2. Gel electrophoresis
  3. Polymerase Chain Reaction (PCR)
  4. DNA sequencing

• Examples: production of insulin, genetically modified organisms

Slide 10

Gene Expression

• Process by which genes are converted into functional proteins

• Regulation of gene expression:

  • Transcription factors
  • DNA methylation
  • Histone modification

• Example: differentiation of cells

Slide 11

Regulation of Gene Expression

• Importance of regulating gene expression

• Types of gene regulation:

  1. Transcriptional regulation
  2. Post-transcriptional regulation
  3. Translational regulation
  4. Post-translational regulation

• Example: lac operon in E. coli

Slide 12

Transcriptional Regulation

• Control of gene expression at the transcriptional level

• Mechanisms of transcriptional regulation:

  1. Promoter regions and transcription factors
  2. Enhancers and silencers
  3. Chromatin remodeling
  4. DNA methylation

• Examples: homeobox genes, tumor suppressor genes

Slide 13

Post-Transcriptional Regulation

• Regulation of gene expression after transcription has occurred

• Mechanisms of post-transcriptional regulation:

  1. mRNA processing (splicing, polyadenylation)
  2. mRNA stability
  3. RNA interference

• Examples: alternative splicing, microRNAs

Slide 14

Translational Regulation

• Control of gene expression at the level of translation

• Mechanisms of translational regulation:

  1. Translational repressors and activators
  2. Ribosome binding sites
  3. RNA secondary structures

• Examples: iron response element (IRE), translational control in oocytes

Slide 15

Post-Translational Regulation

• Regulation of gene expression after translation has occurred

• Mechanisms of post-translational regulation:

  1. Protein folding and modification
  2. Protein degradation
  3. Protein-protein interactions
  4. Signal transduction pathways

• Examples: phosphorylation, ubiquitination

Slide 16

Epigenetics

• Study of heritable changes in gene expression without changes in DNA sequence

• Mechanisms of epigenetic regulation:

  1. DNA methylation
  2. Histone modification
  3. Non-coding RNAs

• Examples: genomic imprinting, X chromosome inactivation

Slide 17

Evolutionary Significance

• Role of molecular basis of inheritance in evolution

• Molecular evidence for evolution:

  1. Comparative genomics
  2. Phylogenetics
  3. Molecular clocks

• Example: homologous genes

Slide 18

Genetic Disorders

• Diseases caused by genetic mutations or abnormalities

• Types of genetic disorders:

  1. Single gene disorders (e.g., cystic fibrosis, Huntington’s disease)
  2. Chromosomal disorders (e.g., Down syndrome, Turner syndrome)
  3. Multifactorial disorders (e.g., diabetes, heart disease)

• Examples: sickle cell anemia, hemophilia

Slide 19

Genetic Engineering

• Manipulation of genes for practical purposes

• Applications of genetic engineering:

  1. Agriculture (crop improvement, pest resistance)
  2. Medicine (gene therapy, production of therapeutic proteins)
  3. Forensics (DNA profiling)
  4. Biotechnology (production of enzymes, biofuels)

• Examples: Golden Rice, genetically engineered insulin

Slide 20

Ethical Considerations

• Moral and societal implications of genetic research and technologies

• Ethical issues in genetics:

  1. Privacy and confidentiality
  2. Genetic discrimination
  3. Designer babies
  4. Patenting of genes

• Examples: genetic testing, cloning

Slide 21

Inheritance Patterns

• Mendelian inheritance

  • Law of segregation
  • Law of independent assortment

• Non-Mendelian inheritance

  • Incomplete dominance
  • Codominance
  • Multiple alleles
  • Polygenic traits

• Examples: Mendel’s pea plant experiments, blood type inheritance

======

Slide 22

Genetic Variation

• Sources of genetic variation

  • Mutation
  • Genetic recombination
  • Sexual reproduction

• Importance of genetic variation

  • Adaptation to changing environments
  • Evolutionary potential

• Examples: DNA mutations, crossing over during meiosis

======

Slide 23

Human Genome Project

• International research project

• Aims:

  • Determine the complete sequence of the human genome
  • Identify genes and their function
  • Understand the genetic basis of diseases

• Impact of the Human Genome Project

  • Advances in personalized medicine
  • Development of gene therapies

• Examples: mapping of human chromosomes, identification of disease-related genes

======

Slide 24

Cloning

• Process of producing genetically identical copies

• Types of cloning:

  • Reproductive cloning
  • Therapeutic cloning

• Applications of cloning:

  • Agriculture (cloning of livestock)
  • Medicine (production of organs for transplantation)

• Example: Dolly the sheep

======

Slide 25

Stem Cells

• Undifferentiated cells with the potential to develop into different cell types

• Types of stem cells:

  • Totipotent
  • Pluripotent
  • Multipotent

• Applications of stem cells:

  • Regenerative medicine
  • Drug development

• Example: use of embryonic stem cells in research

======

Slide 26

Biotechnology

• Application of biological knowledge and techniques to develop products and processes

• Areas of biotechnology:

  • Medical biotechnology
  • Agricultural biotechnology
  • Environmental biotechnology

• Examples: production of recombinant proteins, genetic engineering of crops

======

Slide 27

Genetically Modified Organisms (GMOs)

• Organisms whose genetic material has been altered using genetic engineering techniques

• Examples of GMOs:

  • Genetically modified crops with enhanced traits (e.g., insect resistance, herbicide tolerance)
  • Genetically modified animals for medical research

• Benefits and concerns of GMOs:

  • Increased crop yield and productivity
  • Environmental and health concerns

======

Slide 28

RNA Interference (RNAi)

• Natural process of gene silencing in cells

• Mechanism of RNA interference:

  • Introduction of small RNA molecules to target specific mRNA molecules for degradation
  • Regulation of gene expression

• Applications of RNAi:

  • Functional genomics
  • Therapeutics

• Example: use of RNAi in cancer research

======

Slide 29

Genetic Testing

• Analysis of DNA or proteins to identify genetic disorders or individual traits

• Types of genetic testing:

  • Diagnostic testing
  • Carrier testing
  • Predictive testing

• Uses and limitations of genetic testing:

  • Disease diagnosis and risk assessment
  • Ethical and privacy concerns

• Example: testing for inherited cancer susceptibility genes

======

Slide 30

Genetic Counseling

• Process of providing information and support to individuals and families about genetic disorders

• Goals of genetic counseling:

  • Discussing the risk of inherited disorders
  • Assisting decision-making regarding testing and treatment options
  • Providing emotional support

• Examples: genetic counseling for prenatal screening, family history evaluation