Genetics: L10-C, Chromosome Abnormalities: Pericentric Inversions (Recommend 1.5x Speed)

This educational video from a genetics course explains pericentric inversions, a type of chromosomal inversion that includes the centromere. The instructor uses diagrams to illustrate the formation of a pericentric inversion through two breaks and flipping of a segment. He emphasizes that while the inversion may not disrupt genes if breaks occur in intergenic regions, problems arise during meiosis in inversion heterozygotes. An inversion loop forms to align homologous chromosomes, and if a crossover occurs within this loop, it can produce unbalanced gametes. The video details the outcomes of a single crossover, showing that two chromatids are normal, while the two crossover chromatids have duplications and deficiencies of chromosomal segments, likely leading to inviable zygotes. The explanation contrasts with paracentric inversions, which can create dicentric or acentric chromatids. The video concludes by previewing the next topic on translocations.