Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025
Definition
Paracentric refers to a type of chromosomal inversion that does not include the centromere. This inversion occurs when a segment of a chromosome breaks off, flips around, and reattaches in the reverse orientation without involving the centromere.
Paracentric inversions can lead to the formation of dicentric (two centromeres) or acentric (no centromeres) chromosomes during meiosis if crossing over occurs within the inverted segment.
These inversions typically do not affect the overall phenotypic expression unless they disrupt important genes or regulatory regions.
Paracentric inversions are less likely than pericentric inversions to result in viable offspring due to problems during meiosis.
In heterozygotes, paracentric inversions can cause reduced fertility due to abnormal gamete formation.
Paracentric inversions can be detected through techniques such as karyotyping and fluorescence in situ hybridization (FISH).
Related terms
Pericentric Inversion: A type of chromosomal inversion that includes the centromere, affecting both arms of the chromosome.
Dicentric Chromosome: A chromosome with two centromeres, often resulting from improper crossover events involving an inverted segment.
Acentric Chromosome: A chromosome fragment lacking a centromere, generally leading to its loss during cell division.