LIFE201B DNA Recombination Study Guide

LIFE201B DNA Recombination Study Guide

Vocabulary

• Meiosis

  • Definition: The process by which sexually reproducing organisms produce gametes with haploid genomes. A diploid germ-line parent cell produces four non-identical haploid gametes after meiosis.

• Diploid vs Haploid

  • Diploid: Cells with two entire sets (two copies) of each chromosome.
  • Haploid: Cells with one set of each chromosome.

• Homologous Recombination

  • Definition: A process where DNA information from one chromosome is exchanged with a homologous chromosome. It is crucial for DNA repair and generates genetic diversity in gametes.

• Meiosis I

  • Definition: The first round of cell division in which homologous chromosomes align together and are separated from one another.

• Meiosis II

  • Definition: The second round of cell division where the two cells produced from Meiosis I divide into two daughter cells, resulting in four total cells. Sister chromatids are separated in this division.

• Cross-over

  • Definition: A DNA exchange event where DNA from one chromosome aligns with and becomes integrated into a homologous chromosome.

• Bivalent

  • Definition: A four-chromosome structure where duplicated homologs are closely held together by the synaptonemal complex (SC).

• Holliday Junction

  • Definition: A structure occurring during homologous recombination where two homologous DNA helices are connected by the exchange of two of the four strands of DNA, leading to one pair of strands crossing while another pair does not.

• Non-homologous Recombination

  • Definition: Events in which DNA is exchanged from one chromosome to another without the necessity of homologous sequences.

• Mobile Genetic Element

  • Also known as transposons, these are sequences that can