Contrast the genetic composition of gametes derived from tetrads of inversion heterozygotes where crossing over occurs within a paracentric versus a pericentric inversion.

Key Concepts

Tetrads and Crossing Over

Tetrads are formed during meiosis when homologous chromosomes pair up. Crossing over occurs when segments of DNA are exchanged between these paired chromosomes, leading to genetic recombination. This process increases genetic diversity in gametes, which is crucial for evolution and adaptation.

Paracentric Inversion

Paracentric inversion is a chromosomal rearrangement where a segment of a chromosome is inverted but does not include the centromere. When crossing over occurs in paracentric inversion, it can lead to the formation of acentric fragments and dicentric chromosomes, which can result in gametes with missing or extra genetic material.

Pericentric Inversion

Pericentric inversion involves the inversion of a chromosome segment that includes the centromere. During crossing over in pericentric inversions, the resulting gametes can have duplications and deletions of genetic material, affecting the viability of the gametes and the resulting offspring. This can lead to various genetic disorders or phenotypic variations.