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Questions and Answers
What is a characteristic feature of single nucleotide polymorphisms (SNPs)?
What is a characteristic feature of single nucleotide polymorphisms (SNPs)?
Which of the following is a methodology used for DNA analysis?
Which of the following is a methodology used for DNA analysis?
What is the primary goal of treating genetic diseases?
What is the primary goal of treating genetic diseases?
Which of these methods is associated with cytogenetics?
Which of these methods is associated with cytogenetics?
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What type of genetic alteration might be detected through chromosomal aberrations?
What type of genetic alteration might be detected through chromosomal aberrations?
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Which test involves the use of fluorescently labeled DNA?
Which test involves the use of fluorescently labeled DNA?
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What is typically assessed through biochemical tests in genetic diagnostics?
What is typically assessed through biochemical tests in genetic diagnostics?
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Which of the following is an example of a point mutation?
Which of the following is an example of a point mutation?
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What role do oncogenes play in cancer development?
What role do oncogenes play in cancer development?
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Which statement accurately describes tumor-suppressor genes?
Which statement accurately describes tumor-suppressor genes?
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What does a dominant allele mean in terms of trait expression?
What does a dominant allele mean in terms of trait expression?
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What is a trait in genetic terms?
What is a trait in genetic terms?
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Which term describes the genetic makeup of an organism?
Which term describes the genetic makeup of an organism?
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What is primarily produced by genes in the human body?
What is primarily produced by genes in the human body?
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What characteristic defines a hybrid organism in genetics?
What characteristic defines a hybrid organism in genetics?
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Approximately what percentage of the human genome is thought to encode proteins?
Approximately what percentage of the human genome is thought to encode proteins?
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Which of the following best describes the process of transcription in molecular biology?
Which of the following best describes the process of transcription in molecular biology?
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Which scenario best illustrates codominance?
Which scenario best illustrates codominance?
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What type of genetic disorder results from a mutation in a single gene?
What type of genetic disorder results from a mutation in a single gene?
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What defines a polygenic trait?
What defines a polygenic trait?
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Which statement about repetitive DNA is true?
Which statement about repetitive DNA is true?
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Which of the following genetic diseases is inherited in an autosomal recessive manner?
Which of the following genetic diseases is inherited in an autosomal recessive manner?
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What is the central dogma of molecular biology?
What is the central dogma of molecular biology?
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Which of these conditions is considered complex or multifactorial?
Which of these conditions is considered complex or multifactorial?
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Study Notes
Introduction to Genetics and Pediatric Diseases
- Genetics is the study of heredity, a biological process where parents pass genes to their offspring.
- DNA is the fundamental molecule that contains genetic information in an organism. DNA replicates during reproduction and passes from parent to offspring.
- Genes are located on chromosomes, and both chromosomes and genes are made of DNA.
- Genes act as blueprints for heredity and are composed of hundreds to thousands of DNA bases.
- Genes primarily function by producing proteins.
- Most genes occur in pairs, and members of a gene pair can differ from one another.
- The human genome has 3 billion base pairs of DNA; less than 1.5% encodes proteins.
- About 5% of the genome contains regulatory elements
- About half of the total DNA length is single-copy or unique DNA; the rest is repetitive DNA (e.g., Alu is 10%, and LINE is 20%).
- Most of the ~25,000 genes are located in single-copy DNA.
- Repetitive DNA is involved in chromosome structure and contributes to variation between individuals.
Lecture Outline
- Genes, genome, and chromosomes
- The central dogma of molecular genetics
- Genetics and disease
- Diagnosis of genetic diseases
- Treatment of genetic diseases
- Genetic testing and screening
- Genetic counseling
Basic Facts About Genes and Chromosomes
- Genes are located on chromosomes.
- Chromosomes and genes are made of DNA.
- Genes hold the genetic blueprint for heredity.
- Genes are constructed of hundreds to thousands of DNA bases.
- Genes mostly create proteins.
- Genes usually occur in pairs.
- Members of a gene pair can differ from one another.
The Human Genome
- The human genome contains 3 billion base pairs of DNA.
- Less than 1.5% of DNA encodes proteins.
- Approximately 5% of the genome is believed to contain regulatory elements.
- Only about half the linear length of the genome comprises single-copy/unique DNA.
- The remaining portion consists of several classes of repetitive DNA, such as Alu (10%) and LINE (20%).
- Most genes reside within the single-copy DNA section.
- Repetitive DNA maintains chromosome structure and contributes to differences among individuals.
Inside the Cell (Structure)
- Cells contain a nucleus.
- The nucleus contains chromosomes.
- Chromosomes are made of DNA.
- Genes are segments of DNA.
Chromosomes and Inheritance
- Humans have 46 chromosomes organized in pairs (autosomes and allosomes).
- Autosomes are body chromosomes, and allosomes are sex chromosomes (XY).
Structure of DNA
- DNA is a double helix.
- DNA is organized into nucleosomes ("beads on a string").
- Nucleosomes coil into a solenoid structure;
- The solenoid fibers loop to form an interphase chromosome within the nucleus.
Central Dogma of Molecular Biology
- DNA replicates to create more DNA.
- DNA transcribes to produce RNA.
- RNA is translated to provide instructions for protein production.
- The process flows from DNA to RNA to protein.
Parts of a Gene
- Regulatory elements (enhancers, promoters) regulate gene expression; determine how much, in what tissue, and when a gene is expressed.
- Protein-coding sequence translates to a protein product.
Genes and Disease
- Mutations can cause changes in genes, leading to health problems.
- Single-gene disorders show varying inheritance patterns (autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive).
Cancer Genetics and Genomics
- Cancer arises from an imbalance between cellular proliferation and cellular attrition.
- Cancer affects over one-third of the population and accounts for a significant portion of deaths worldwide.
Genes in Which Mutations Cause Cancer
- Oncogenes stimulate uncontrolled cell growth or inhibit apoptosis (programmed cell death).
- Tumor-suppressor genes (TSGs) regulate cell-cycle checkpoints and mediate programmed cell death.
- Caretaker genes maintain genomic integrity by detecting and repairing mutations, along with ensuring proper chromosome division during mitosis.
What is Inheritance?
- All living organisms inherit traits from their parents.
- Genetics is the scientific study of heredity.
Vocabulary to Know
- Trait: A characteristic, like eye color.
- Gene: A section of DNA determining a trait.
- Hybrid: Offspring of parents with different traits.
- Gamete: A reproductive cell (e.g., sperm and egg).
- Allele: Different forms of a gene.
- Dominant allele: A trait expressed with only one copy.
- Recessive allele: A trait expressed only when no dominant allele is present
- Genotype: The combination of alleles, what the genes say.
- Phenotype: The observable trait, like widow's peak.
- Codominance: Both alleles contribute to the phenotype.
- Multiple alleles: Involve more than two allele possibilities, such as blood type.
- Polygenic traits: Traits determined by more than one gene, like skin color.
Allele Combinations
- Homozygous: Both alleles are the same (WW or ww).
- Heterozygous: Alleles are different (Ww)
Genotype and Phenotype
- Genotype: The combination of alleles an organism has.
- Phenotype: The observable trait.
Codominance
- Both alleles contribute to the phenotype.
Multiple Alleles
- More than two possibilities for alleles, like blood type.
Polygenic Traits
- Traits determined by more than one gene.
Classification of Genetic Disorders
- Single-gene disorders
- Chromosomal disorders
- Multifactorial disorders
Variation in Chromosomal Structure
- Deletion
- Duplication
- Translocation
Human Chromosome Abnormalities
- Variations in the number of chromosomes, or variations in their structure, can lead to health issues.
Aneuploidy
- A term for variations in the number of chromosomes; not an exact multiple of the standard number (n) of chromosomes.
- Types such as Monosomy, Trisomy, Tetrasomy, Double trisomy, and Nullosomy.
Euploidy/Polyploidy
- An increase in chromosome number due to complete chromosome sets.
- Types include Monoploid, Diploid, Triploid, Tetraploid, Autotetraploid, and Polyploid.
Sex Chromosome Anomalies
- Turner's syndrome (45,X0)
- Klinefelter's syndrome (47,XXY)
- Jacob's syndrome (47,XYY)
- Triple X syndrome (47,XXX)
Structural Sex Chromosome Anomalies
- Y-linked diseases (very rare)
- X-linked diseases (recessive or dominant)
Mendelian Disorders
- Genetic conditions caused by mutations in a single gene.
- Autosomal dominant diseases.
- Autosomal recessive diseases.
- X-linked recessive diseases.
- X-linked dominant diseases
Mitochondrial Disorders
- Mitochondrial DNA (mtDNA) is passed from mothers to their offspring.
- Mitochondrial diseases are inherited from the mother.
Prenatal Genetic Tests
- Amniocentesis and chorionic villus sampling collect fetal cells or fluid for testing.
- Karyotyping and enzyme analyses.
- Used to assess fetal health and diagnose diseases.
Genetic Testing/Screening
- The decision to pursue genetic testing and screening.
- Tests to determine carrier status for future children.
- Prenatal diagnosis
Genetic Counselors
- Provide information, support, and guidance about genetic conditions.
- Analyze inheritance and recurrence patterns.
- Identify risk families.
- Evaluate available options (treatment, care).
Prevention of Genetic Diseases
- Genetic counseling, expert consultation, to determine risk and inheritance patterns for potential genetic disorders.
Pedigree and Karyotype
- Pedigree: A family tree showing traits across multiple generations
- Karyotype: An analysis of chromosome structure and number in a sample of cells.
Methods for Studying Genetics
- PCR (Polymerase Chain Reaction): A method for amplifying specific DNA sequences.
- Southern blotting: Used to detect specific DNA sequences in a sample.
- DNA sequencing
- Single Nucleotide Polymorphism (SNP)
- Fluorescent In-situ Hybridization (FISH)
- Microarrays
- Karyotyping
- Gel electrophoresis
- Restriction Fragment Length Polymorphism (RFLP)
Diagnosis and Treatment of Genetic Diseases
- DNA, RNA, and protein-based diagnostics are used for diagnosis.
- Mutations (point mutations, insertions/deletions, frameshift mutations, chromosomal aberrations).
- Treatment focuses on managing symptoms and alleviating effects of genetic disorders.
- Therapy to modify individual behaviors (treatment) at the level of gene expression, protein folding.
- Approaches for modifying somatic genomes via transplantation techniques (stem cell, nuclear transplantation).
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Description
Explore the fundamentals of genetics, focusing on how heredity works and the role of DNA in organism development. Understand the significance of genes, their structure, and how they contribute to pediatric diseases. This quiz covers essential aspects of genetics that are crucial for understanding hereditary conditions.
