TEL - genetic variation and pedigree analysis

Dominant autosomal inheritance

A type of inheritance where a trait is expressed even if only one copy of the allele is present.

Recessive autosomal inheritance

A type of inheritance where a trait is expressed only when both copies of the allele are present.

Y-Chromosome linked inheritance

Inheritance pattern where genes are located only on the Y chromosome, requiring only one copy to express traits.

X-Chromosome linked dominance inheritance

A pattern where a trait is expressed if at least one X chromosome carries the dominant allele.

X-Chromosome linked recessive inheritance

A pattern where a trait is expressed when both X chromosomes carry the recessive allele in females, and when the single X chromosome in males carries the recessive allele.

Diploid

An organism or cell having two sets of chromosomes (2n), one from each parent.

Haploid

A cell that contains only one set of chromosomes (n), such as gametes.

Autosomal chromosomes

Chromosomes that are not sex chromosomes; in humans, there are 22 pairs.

Sex chromosomes

Chromosomes that determine the sex of an individual; in humans, these are X and Y.

Homologous chromosomes

A pair of chromosomes containing the same genes but may have different alleles.

Pedigree analysis

A diagram that depicts family relationships and inheritance patterns of traits.

Dominant trait

A trait that appears in the phenotype when at least one dominant allele is present.

Recessive trait

A trait that only appears in the phenotype when two recessive alleles are present.

X-linked recessive traits

Traits that predominantly affect males because they have only one X chromosome.

MeCP2 gene

Gene associated with Rett syndrome located on the X chromosome.

Complete penetrance

Situation where all individuals with a mutant genotype display the phenotype.

Partial gene deletion

Missing pieces of a chromosome that can lead to genetic disorders.

Uniparental disomy

Condition where both copies of a chromosome come from one parent.

Genomic imprinting

An epigenetic phenomenon where certain genes are expressed in a parent-of-origin-specific manner.

UBE3A gene

Gene implicated in Angelman syndrome, located on chromosome 15.

Angelman syndrome

A genetic disorder characterized by delayed development, intellectual disability, and ataxia.

Phenotypic expression

Observable characteristics that result from the interaction of an individual's genotype with the environment.

Transcriptional repressor

A protein that inhibits the expression of one or more genes.

Nucleotide polymorphism

Variations at a single nucleotide position in the DNA sequence among individuals.

Polymerase Chain Reaction (PCR)

A technique used to amplify specific segments of DNA.

Hybridization techniques

Methods used to detect specific sequences of nucleic acids.

FISH (Fluorescent In Situ Hybridization)

Technique that uses fluorescent probes to detect specific DNA sequences.

DNA microarray technology

A tool used to detect gene expression or genetic mutations at high throughput.

Genome sequencing

Determining the complete DNA sequence of an organism's genome.

Ataxia-telangiectasia

A rare inherited disorder affecting the nervous and immune systems.

ATM gene

Gene linked to Ataxia-telangiectasia that helps in DNA repair.

Inheritance pattern

The manner in which a genetic trait or disorder is transmitted from parent to offspring.

Single nucleotide polymorphism (SNP)

A single base-pair variation in the DNA sequence.

Point mutation

A mutation in which a single nucleotide in DNA is changed.

Methylation

Addition of methyl groups to DNA that can regulate gene expression by silencing genes.

Heterozygous

Having two different alleles for a particular gene.

Homozygous

Having two identical alleles for a particular gene.

Dominant allele

An allele that can mask the expression of a recessive allele.

Recessive allele

An allele whose expression is only seen when paired with another recessive allele.

Malformation syndromes

Disorders caused by abnormal development of tissues and organs.

Transcription factor

Proteins that bind to specific DNA sequences to regulate gene expression.

Proteasome

A cellular structure that degrades unneeded or damaged proteins.

Gene therapy

A potential therapeutic approach aimed at correcting defective genes.