- Genetics and Evolution - Molecular Basis of Inheritance
- Introduction to the topic: Molecular Basis of Inheritance
- Definition: The study of how genetic information is stored, transferred, and expressed in living organisms
- Importance: Understanding the molecular mechanisms of inheritance is crucial to understand genetic disorders, evolution, and biotechnology applications
- DNA and RNA: Building Blocks of Genetic Information
- DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid)
- Structure of DNA: Double helix, composed of nucleotides (phosphate, sugar, and nitrogenous base)
- Types of RNA: Messenger RNA (mRNA), Transfer RNA (tRNA), Ribosomal RNA (rRNA)
- Role of DNA and RNA: DNA stores genetic information, while RNA carries out protein synthesis
- Central Dogma of Molecular Biology
- Central Dogma: The flow of genetic information from DNA to RNA to protein
- DNA Replication: Process of DNA synthesis, ensures accurate transmission of genetic information during cell division
- Transcription: DNA is used as a template to synthesize mRNA
- Translation: mRNA is decoded by ribosomes to produce proteins
- Genetic Code
- Genetic code: The set of rules which determine the translation of mRNA nucleotide sequence into amino acid sequence
- Codons: Three-nucleotide sequences on mRNA that code for specific amino acids
- Start codon: AUG (codes for methionine), initiates protein synthesis
- Stop codons: UAA, UAG, UGA, signify the end of protein synthesis
- Protein Synthesis
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Step 1: Transcription
- Initiation: RNA polymerase binds to the promoter region of DNA
- Elongation: RNA polymerase synthesizes mRNA using DNA as a template
- Termination: RNA polymerase reaches the terminator sequence, mRNA is released
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Step 2: Translation
- Initiation: Ribosomes bind to mRNA at the start codon
- Elongation: tRNA carries amino acids to the ribosome, forming a polypeptide chain
- Termination: Ribosome encounters a stop codon, polypeptide is released
- Mutations: Changes in Genetic Information
- Mutations: Changes in DNA sequence that can lead to genetic variability
- Types of mutations: Point mutations, frameshift mutations, chromosomal mutations
- Effects of mutations: Silent mutations, missense mutations, nonsense mutations
- Impact of mutations: Can cause genetic disorders, contribute to evolution, or have no significant effect
- Recombinant DNA Technology
- Recombinant DNA: DNA that is formed by combining DNA fragments from different sources
- Techniques in recombinant DNA technology: Restriction enzymes, DNA ligation, Polymerase Chain Reaction (PCR)
- Applications of recombinant DNA technology: Gene cloning, production of genetically modified organisms (GMOs), gene therapy
- Genomic Organization and Gene Expression Regulation
- Genomic organization: The way genes are arranged on chromosomes
- Prokaryotic gene expression regulation: Operon model (lac operon, trp operon)
- Eukaryotic gene expression regulation: Enhancers, silencers, transcription factors, epigenetic modifications
- DNA Replication: The Molecular Basis of Heredity
- DNA replication: Process by which a DNA molecule is copied to produce two identical DNA molecules
- Steps of DNA replication: Initiation, elongation, termination
- Enzymes involved in DNA replication: DNA helicase, DNA polymerase, DNA ligase
- Significance of DNA replication: Ensures inheritance of genetic information during cell division
- Transcription and Translation: Gene Expression
- Transcription: Process of synthesizing an mRNA molecule using DNA as a template
- Translation: Process of decoding the mRNA molecule to synthesize proteins
- Differences between transcription and translation: Location, involvement of different molecules, final product
- Genetics and Evolution - Molecular Basis of Inheritance - What are the functions of Cap
- Introduction to Cap: Cap refers to the capped structure found at the 5’ end of eukaryotic mRNA
- Functions of Cap:
- Protection: Cap protects the mRNA from degradation by exonucleases
- Ribosome binding: Cap helps in the binding of ribosomes to initiate translation
- Enhancing mRNA stability: Cap contributes to the stability of mRNA molecules
- Genetics and Evolution - Molecular Basis of Inheritance - What is Alternative Splicing?
- Definition of Alternative Splicing: A process in which different combinations of exons are spliced together to generate multiple mRNA isoforms from a single gene
- Importance of Alternative Splicing:
- Increases proteome diversity: Allows for the production of different protein isoforms from a single gene
- Regulation of gene expression: Alternative splicing can regulate the expression of certain genes by including or excluding specific exons
- Functional diversity: Results in proteins with different functions or properties
- Genetics and Evolution - Molecular Basis of Inheritance - What is a DNA Marker?
- Definition of DNA Marker: A specific DNA sequence used to identify and locate genes or genetic variations in individuals or populations
- Types of DNA markers:
- Restriction Fragment Length Polymorphisms (RFLPs)
- Microsatellites (Short Tandem Repeats, STRs)
- Single Nucleotide Polymorphisms (SNPs)
- Applications of DNA markers: Genetic mapping, forensic science, paternity testing, population genetics studies
- Genetics and Evolution - Molecular Basis of Inheritance - What is Genetic Engineering?
- Definition of Genetic Engineering: The manipulation of an organism’s genetic material to alter its characteristics or create new traits
- Techniques in genetic engineering:
- Recombinant DNA technology: Combining DNA from different sources
- Gene editing: Modifying existing DNA sequences using CRISPR/Cas9 or other tools
- Applications of genetic engineering: Agriculture, medicine, environmental remediation
- Genetics and Evolution - Molecular Basis of Inheritance - What is DNA Fingerprinting?
- Definition of DNA Fingerprinting: A technique used to identify and compare individuals based on their unique DNA profiles
- Steps involved in DNA fingerprinting:
- DNA extraction: Isolation of DNA from a biological sample (e.g. blood, saliva)
- Polymerase Chain Reaction (PCR): Amplification of specific DNA regions
- Gel Electrophoresis: Separation of DNA fragments based on size
- DNA profiling: Comparison of DNA banding patterns to establish identity or relationships
- Genetics and Evolution - Molecular Basis of Inheritance - What is Genetic Counseling?
- Definition of Genetic Counseling: A process that helps individuals or families understand and adapt to the implications of a genetic disorder or genetic risk
- Goals of genetic counseling:
- Provide information and education about genetic conditions
- Assess individual or family risk factors
- Discuss options for testing, treatment, and reproductive choices
- Offer emotional support and guidance for coping with genetic conditions
- Genetics and Evolution - Molecular Basis of Inheritance - What are the different patterns of inheritance?
- Mendelian patterns of inheritance:
- Autosomal dominant: Inheritance of a dominant allele on an autosome
- Autosomal recessive: Inheritance of a recessive allele on an autosome
- X-linked dominant: Inheritance of a dominant allele on the X chromosome
- X-linked recessive: Inheritance of a recessive allele on the X chromosome
- Non-Mendelian patterns of inheritance: Incomplete dominance, codominance, polygenic traits, multifactorial inheritance
- Genetics and Evolution - Molecular Basis of Inheritance - Example: Autosomal Dominant Inheritance
- Definition of Autosomal Dominant Inheritance: Inheritance pattern where a single copy of the dominant allele is sufficient to cause the trait or disorder
- Example: Huntington’s disease
- Causative gene: HTT gene on chromosome 4
- Symptoms: Progressive degeneration of brain cells, movement disorders, cognitive decline
- Inheritance: Offspring of an affected parent have a 50% chance of inheriting the disease
- Genetics and Evolution - Molecular Basis of Inheritance - Example: Autosomal Recessive Inheritance
- Definition of Autosomal Recessive Inheritance: Inheritance pattern where two copies of the recessive allele are required to manifest the trait or disorder
- Example: Cystic fibrosis
- Causative gene: CFTR gene on chromosome 7
- Symptoms: Lung infections, digestive problems, salt imbalance
- Inheritance: Offspring of carrier parents have a 25% chance of inheriting the disease
- Genetics and Evolution - Molecular Basis of Inheritance - Example: X-Linked Recessive Inheritance
- Definition of X-Linked Recessive Inheritance: Inheritance pattern where the recessive allele is carried on the X chromosome
- Example: Hemophilia
- Causative genes: F8 gene (Hemophilia A) and F9 gene (Hemophilia B)
- Symptoms: Impaired blood clotting, excessive bleeding
- Inheritance: Sons of carrier mothers have a 50% chance of inheriting the disease, while daughters have a 50% chance of being carriers
- Genetics and Evolution - Molecular Basis of Inheritance - What are the functions of Cap
- Definition of Cap: The capped structure found at the 5’ end of eukaryotic mRNA
- Functions of Cap:
- Protection: Cap protects the mRNA from degradation by exonucleases
- Ribosome binding: Cap helps in the binding of ribosomes to initiate translation
- Enhancing mRNA stability: Cap contributes to the stability of mRNA molecules
- Genetics and Evolution - Molecular Basis of Inheritance - What is Alternative Splicing?
- Definition of Alternative Splicing: A process in which different combinations of exons are spliced together to generate multiple mRNA isoforms from a single gene
- Importance of Alternative Splicing:
- Increases proteome diversity: Allows for the production of different protein isoforms from a single gene
- Regulation of gene expression: Alternative splicing can regulate the expression of certain genes by including or excluding specific exons
- Functional diversity: Results in proteins with different functions or properties
- Genetics and Evolution - Molecular Basis of Inheritance - What is a DNA Marker?
- Definition of DNA Marker: A specific DNA sequence used to identify and locate genes or genetic variations in individuals or populations
- Types of DNA markers:
- Restriction Fragment Length Polymorphisms (RFLPs)
- Microsatellites (Short Tandem Repeats, STRs)
- Single Nucleotide Polymorphisms (SNPs)
- Applications of DNA markers: Genetic mapping, forensic science, paternity testing, population genetics studies
- Genetics and Evolution - Molecular Basis of Inheritance - What is Genetic Engineering?
- Definition of Genetic Engineering: The manipulation of an organism’s genetic material to alter its characteristics or create new traits
- Techniques in genetic engineering:
- Recombinant DNA technology: Combining DNA from different sources
- Gene editing: Modifying existing DNA sequences using CRISPR/Cas9 or other tools
- Applications of genetic engineering: Agriculture, medicine, environmental remediation
- Genetics and Evolution - Molecular Basis of Inheritance - What is DNA Fingerprinting?
- Definition of DNA Fingerprinting: A technique used to identify and compare individuals based on their unique DNA profiles
- Steps involved in DNA fingerprinting:
- DNA extraction: Isolation of DNA from a biological sample (e.g., blood, saliva)
- Polymerase Chain Reaction (PCR): Amplification of specific DNA regions
- Gel Electrophoresis: Separation of DNA fragments based on size
- DNA profiling: Comparison of DNA banding patterns to establish identity or relationships
- Genetics and Evolution - Molecular Basis of Inheritance - What is Genetic Counseling?
- Definition of Genetic Counseling: A process that helps individuals or families understand and adapt to the implications of a genetic disorder or genetic risk
- Goals of genetic counseling:
- Provide information and education about genetic conditions
- Assess individual or family risk factors
- Discuss options for testing, treatment, and reproductive choices
- Offer emotional support and guidance for coping with genetic conditions
- Genetics and Evolution - Molecular Basis of Inheritance - What are the different patterns of inheritance?
- Mendelian patterns of inheritance:
- Autosomal dominant: Inheritance of a dominant allele on an autosome
- Autosomal recessive: Inheritance of a recessive allele on an autosome
- X-linked dominant: Inheritance of a dominant allele on the X chromosome
- X-linked recessive: Inheritance of a recessive allele on the X chromosome
- Non-Mendelian patterns of inheritance: Incomplete dominance, codominance, polygenic traits, multifactorial inheritance
- Genetics and Evolution - Molecular Basis of Inheritance - Example: Autosomal Dominant Inheritance
- Definition of Autosomal Dominant Inheritance: Inheritance pattern where a single copy of the dominant allele is sufficient to cause the trait or disorder
- Example: Huntington’s disease
- Causative gene: HTT gene on chromosome 4
- Symptoms: Progressive degeneration of brain cells, movement disorders, cognitive decline
- Inheritance: Offspring of an affected parent have a 50% chance of inheriting the disease
- Genetics and Evolution - Molecular Basis of Inheritance - Example: Autosomal Recessive Inheritance
- Definition of Autosomal Recessive Inheritance: Inheritance pattern where two copies of the recessive allele are required to manifest the trait or disorder
- Example: Cystic fibrosis
- Causative gene: CFTR gene on chromosome 7
- Symptoms: Lung infections, digestive problems, salt imbalance
- Inheritance: Offspring of carrier parents have a 25% chance of inheriting the disease
- Genetics and Evolution - Molecular Basis of Inheritance - Example: X-Linked Recessive Inheritance
- Definition of X-Linked Recessive Inheritance: Inheritance pattern where the recessive allele is carried on the X chromosome
- Example: Hemophilia
- Causative genes: F8 gene (Hemophilia A) and F9 gene (Hemophilia B)
- Symptoms: Impaired blood clotting, excessive bleeding
- Inheritance: Sons of carrier mothers have a 50% chance of inheriting the disease, while daughters have a 50% chance of being carriers