Gentics Exam 1

Hereditary

Biological process through which genetic traits, characteristics, or conditions are passed from one generation to the next through DNA.

Genetic Inheritance

Process by which genetic information is passed from parents to their offspring through DNA, influencing traits and likelihood of developing certain conditions.

Genetic Trait

A characteristic or feature of an organism determined by one or more genes and may be influenced by the environment.

Gene

Segment of DNA that contains instructions necessary to produce a functional molecule, usually a protein or functional RNA.

Human Karyotype

The number and appearance of chromosomes in the nucleus of a eukaryotic cell.

Diploid

Cell that contains two complete sets of chromosomes, one from each parent.

Haploid

Cell that contains one complete set of chromosomes.

DNA

Molecule that carries the genetic instructions used in growth, development, functioning, and reproduction of all known living organisms.

Central Dogma

The process by which the information in genes flows into proteins: DNA → RNA → Protein.

Epigenetics

Study of changes in gene expression that do not involve alterations to the DNA sequence.

Codominance

A genetic phenomenon where both alleles in a heterozygous genotype are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive.

Mitochondrial inheritance

Type of genetic inheritance that occurs only through maternal genes.

Polyadenylation

Process that adds a poly-A tail to a messenger RNA (mRNA), which helps in nuclear export, translation, and stability.

Transcription

Process by which a segment of DNA is copied into RNA by the enzyme RNA polymerase.

Gene Diversity

Differences in timing and rate of expression of the gene, and variations in structure and function of the gene product.

X-inactivation

Process by which one of the X chromosomes is randomly inactivated in female mammals.

Variable expressivity

Variation in the severity of a phenotype among individuals with the same genotype.

Penetrance

The proportion of individuals with a specified genotype that actually express the expected phenotype.

Alu elements

Short stretches of DNA originally identified in the human genome by the action of the Alu restriction enzyme.

Transposons

Segments of DNA that can move from one location in the genome to another.

Heterochromatin

Tightly packed form of DNA that is transcriptionally inactive.

Euchromatin

Loosely packed form of DNA that is generally active in transcription.

Telomeres

Repetitive nucleotide sequences at the ends of linear chromosomes that protect them from degradation.

SNP (Single Nucleotide Polymorphism)

A variation at a single position in a DNA sequence among individuals.

Nucleotide excision repair

Mechanism that cells use to repair UV damage to DNA.

Molecular consequences of mutation

Effects that changes in DNA sequence have on gene function, potentially leading to disease.

Missense mutation

A point mutation that results in the substitution of one amino acid for another in the protein product.

Nonsense mutation

A mutation that creates a premature stop codon, leading to a truncated protein.

Deletion mutation

A mutation that involves the removal of a nucleotide from the DNA sequence.

Insertion mutation

A mutation that involves the addition of one or more nucleotides into the DNA sequence.

Duplication mutation

A mutation involving the production of one or more copies of any piece of DNA.

Framework shift mutation

A genetic mutation caused by insertion or deletion of nucleotides that alters the reading frame of the gene.

Germline mutation

A mutation that occurs in germ cells and can be transmitted to offspring.

Somatic mutation

A mutation that occurs in non-germline tissues and cannot be passed to offspring.

Post-translation modification

Chemical modifications that occur to a protein after translation.

Anticipation

A genetic phenomenon in which a genetic disorder is passed on to the next generation, with symptoms appearing at an earlier age or with increased severity.

Mosaicism

Presence of genetically different cell lines in an individual.

Thalidomide

A drug that was found to cause birth defects but is also used for treatment in some medical conditions.

Cystic fibrosis

An autosomal recessive genetic disorder affecting the lungs and pancreas.

Sickle cell anemia

A genetic disorder characterized by the production of abnormal hemoglobin, leading to distorted red blood cells.

Huntington's Disease

A genetic disorder caused by a mutation in the HTT gene, characterized by progressive neurological decline.

Phenylketonuria (PKU)

An autosomal recessive disorder characterized by the inability to metabolize phenylalanine.

Chromosomal abnormality

Any changes in the structure or number of chromosomes that can lead to genetic disorders.

Types of DNA Repair

Mechanisms used by cells to correct damage to their DNA.

Base Excision Repair (BER)

A repair process that removes and replaces damaged or non-canonical bases in DNA.

Nucleotide Excision Repair (NER)

A repair pathway that removes bulky DNA adducts and lesions, such as those caused by UV light.

Mismatch Repair (MMR)

A repair system that corrects base pair mismatches that occur during DNA replication.

Double-Strand Break Repair (DSBR)

Processes including homologous recombination (HR) and non-homologous end joining (NHEJ) to repair breaks in both strands of DNA.

Homologous Recombination (HR)

A type of double-strand break repair that uses a homologous template to accurately repair DNA.

Non-Homologous End Joining (NHEJ)

A pathway that repairs double-strand breaks without the need for a homologous template, often resulting in deletions.

Translesion Synthesis (TLS)

A DNA damage tolerance process that allows the DNA replication machinery to replicate past DNA lesions.

Error-Prone Repair

Mechanisms that repair DNA damage but may introduce mutations, such as certain forms of NHEJ.

Photoreactivation

A specific repair mechanism that directly reverses UV-induced pyrimidine dimers.

Base Repair Mechanisms

Processes involved in the repair of specific types of base damage to prevent mutations.