Definition

Noun (Genetics, Medicine): A chromosomal condition characterized by the presence of one or more extra copies of a specific chromosome in the somatic (body) cells of an organism. It is a type of aneuploidy, which is an abnormal number of chromosomes.

Usage

"Polysomy" is a technical term used primarily in genetics, cytogenetics, and medical diagnostics. It describes a specific congenital (present from birth) defect or abnormality in the chromosome complement. * The term is often followed by the specific chromosome involved (e.g., polysomy X, polysomy 21). * It is used in contrast to other conditions like monosomy (missing one chromosome) or disomy (the normal two copies).

Examples

• In a medical report: "The karyotype analysis confirmed a diagnosis of polysomy X, also known as Triple X syndrome."
• In a genetics textbook: "Polysomy for autosomes is often not compatible with life, though some specific cases, like trisomy 21, are well-documented."
• In a research context: "The study investigated the cellular mechanisms that lead to polysomy in developing embryos."

Advanced Usage

• Partial Polysomy: Refers to a condition where only a segment of a chromosome is present in extra copies, rather than the entire chromosome.
• The term is often used in its numerical form, such as trisomy (three copies, a specific type of polysomy), tetrasomy (four copies), or pentasomy (five copies).

Variants and Related Words

• Polysomic (Adjective): Relating to or characterized by polysomy.
  • Example: "The polysomic cell line was used for the experiment."
• Aneuploidy (Noun): The broader category of chromosomal number abnormalities that includes polysomy, monosomy, and nullisomy.
• Trisomy (Noun): The most common type of polysomy, involving three copies of a particular chromosome (e.g., Trisomy 21 - Down syndrome).

Synonyms

• Hyperploidy (specifically for gains of whole chromosomes, though this term can include polyploidy).
• Chromosomal duplication (in a general sense, though this can also refer to duplications within a chromosome).

Antonyms

• Monosomy: The condition of having only one copy of a particular chromosome in somatic cells.
• Disomy: The normal state of having two copies of each chromosome (euploidy for diploid organisms).

Noun

1. congenital defect of having one or more extra chromosomes in somatic cells