Genetic Mutations & Chromosomal Abnormalities Lecture

Vocabulary flashcards covering key terms related to population genetics, types of mutations, specific genetic disorders, and chromosomal abnormalities presented in the lecture.

Species

A group of similar individuals capable of interbreeding under natural conditions to produce fertile offspring.

Allele

An alternative form of a gene.

Population

A group of organisms of the same species living together in a particular place at a particular time.

Geneticist

A scientist who specializes in the study of inheritance.

Gene Pool

The total collection of alleles present in a population.

Allele Frequency

The proportion of a specific allele within a gene pool.

Evolution

A change in the characteristics of a species over time.

Phenotype

The observable physical appearance of an organism.

Genotype

The genetic makeup of an organism.

Mutation

A permanent structural alteration in an organism’s DNA.

Spontaneous Mutation

A mutation that arises randomly and suddenly, often from errors in replication or cell division.

Induced Mutation

A mutation caused by environmental factors known as mutagens.

Mutagen

An environmental agent that induces mutations in DNA.

Chemical Mutagen

A chemical substance such as mustard gas or formaldehyde that can cause DNA mutations.

Physical Mutagen

A form of radiation (e.g., UV rays, X-rays) that can damage DNA.

Gene Mutation

A change affecting the base sequence of a single gene.

Chromosome Mutation (Block Mutation)

A change in chromosome structure involving large segments and multiple genes.

Somatic Mutation

A mutation occurring in body (somatic) cells; affects only the individual, not offspring.

Germ-Line (Germinal) Mutation

A mutation in reproductive cells; can be inherited by offspring.

Point Mutation

A mutation affecting a single nucleotide in DNA.

Substitution

A point mutation where one nucleotide is replaced by another.

Neutral Mutation

A substitution that changes an amino acid but does not alter protein function.

Synonymous (Silent) Mutation

A substitution that does not change the amino-acid sequence due to redundancy in the genetic code.

Missense Mutation

A substitution that changes an amino acid, potentially altering protein function.

Nonsense Mutation

A substitution introducing a premature stop codon, producing an incomplete polypeptide.

Frameshift Mutation

A mutation (insertion or deletion) that shifts the reading frame, altering downstream codons.

Insertion

Addition of one or more nucleotides into DNA.

Deletion

Removal of one or more nucleotides from DNA.

Indel

Collective term for insertions and deletions in DNA.

Albinism

A disorder caused by lack of melanin pigment, resulting in very pale skin, white hair, and often vision problems.

Duchenne Muscular Dystrophy

X-linked mutation in the dystrophin gene leading to progressive muscle wasting and early death.

Cystic Fibrosis

Autosomal recessive disorder due to mutation on chromosome 7 affecting chloride ion transport; causes thick mucus and respiratory issues.

Lethal Recessive

A recessive allele that causes death of an embryo, fetus, or young child when homozygous.

Tay-Sachs Disease

Autosomal recessive disorder caused by HEXA gene mutation leading to GM2 ganglioside buildup and neurodegeneration.

Deletion (Chromosomal)

Loss of a chromosome segment, removing several genes; often fatal.

Inversion

A chromosome segment breaks off, rotates 180°, and re-attaches, reversing gene order.

Translocation

A segment of one chromosome detaches and attaches to another chromosome, disrupting gene regulation.

Duplication

An extra copy of a chromosome segment is inserted, increasing gene dosage.

Aneuploidy

Addition or loss of a single chromosome due to non-disjunction.

Non-Disjunction

Failure of homologous chromosomes or sister chromatids to separate during meiosis.

Trisomy

Presence of three copies of a particular chromosome (2n+1).

Down Syndrome (Trisomy 21)

Condition caused by an extra chromosome 21, leading to characteristic physical traits and developmental delays.

Edwards Syndrome (Trisomy 18)

Aneuploidy involving chromosome 18, associated with severe developmental abnormalities.

Patau Syndrome (Trisomy 13)

Aneuploidy involving chromosome 13, resulting in multiple organ defects and high infant mortality.

Klinefelter Syndrome (47,XXY)

Male aneuploidy with an extra X chromosome; features include tall stature, reduced musculature, and infertility.

Turner Syndrome (45,XO)

Female aneuploidy with a single X chromosome; features include short stature and underdeveloped ovaries.

Syndrome

A disease or disorder with multiple distinct effects or symptoms.

Partial Monosomy

Loss of a portion of a chromosome.

Partial Trisomy

Presence of an extra segment attached to a chromosome.

Amniocentesis

Prenatal test where amniotic fluid is sampled to analyze fetal chromosomes.

Chorionic Villus Sampling (CVS)

Prenatal test obtaining placental tissue to examine fetal chromosomes.

Phenylketonuria (PKU)

Inherited metabolic disorder caused by germ-line mutation, leading to phenylalanine buildup if untreated.