CELS191 Lecture 17: X-Inactivation

This set of flashcards covers key concepts and terms related to X-inactivation, genetics, and related conditions discussed in CELS191 lecture 17.

Lyon Hypothesis

The hypothesis stating that in females, one of the two X chromosomes is randomly inactivated during development.

Barr Body

A highly condensed structure representing an inactivated X chromosome found in the nuclei of female cells.

X-Inactivation

The process by which one X chromosome in female mammals is inactivated to balance dosages of X-linked genes.

Dosage Compensation

The mechanism that equalizes the gene expression levels of X-linked genes between males and females.

Mosaicism

A condition where an individual has two or more genetically different cell lines, seen in females due to X-inactivation.

Genomic Imprinting

A genetic phenomenon where certain genes are expressed in a parent-of-origin-specific manner.

Phenotypic Plasticity

The ability of an organism to change its phenotype in response to environmental conditions.

Aneuploidy

A condition in which there is an abnormal number of chromosomes in a cell.

Klinefelter Syndrome

A genetic condition in males characterized by the presence of an extra X chromosome (XXY).

Turner Syndrome

A genetic disorder in females characterized by the complete or partial absence of one X chromosome (XO).

Sex Chromosomes

Chromosomes (X and Y) that determine the sex of an individual.

Autosomes

Chromosomes that are not sex chromosomes, numbered 1 to 22 in humans.

X-Linked Genes

Genes located on the X chromosome, can lead to different traits in males and females.

Calico Cat

A cat breed that exhibits a mosaic pattern of coat color due to X-inactivation.

Haemophilia

A genetic disorder that affects the body's ability to clot blood, often linked to X-inactivation.

G6PDH Deficiency

An X-linked genetic disorder that can lead to red blood cell destruction under certain conditions.

XYY Syndrome

A genetic condition in males characterized by the presence of an extra Y chromosome.

XXX Syndrome

A genetic condition in females characterized by the presence of an extra X chromosome.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by genetics and environment.

Alleles

Different versions of a gene that can exist at the same locus on homologous chromosomes.

Genetic Dosage

The number of copies of a given gene that an organism possesses.