Recombination Vocabulary

Flashcards covering key vocabulary terms related to recombination, as discussed in Dr. Frank Stearns' BIO 330 lecture on Spring 2025.

Somatic recombination

Recombination that occurs in nongerm cells; most commonly used to refer to recombination in the immune system.

Sister chromatid

Each of two identical copies of a replicated chromosome; this term is used as long as the two copies remain linked at the centromere.

Bivalent

The structure containing all four chromatids (two representing each homolog) at the start of meiosis.

Synaptonemal complex

The morphological structure of synapsed chromosomes.

Joint molecule

A pair of DNA duplexes that are connected together through a reciprocal exchange of genetic material.

D-loop

Branched structure created when a single strand from one duplex displaces its counterpart in the other duplex during double-strand break repair.

Branch migration

The ability of a DNA strand partially paired with its complement in a duplex to extend its pairing by displacing the resident strand with which it is homologous.

Gene conversions

Nonreciprocal recombinant products resulting from mismatch repair of heteroduplex DNA.

Break-induced replication (BIR)

Replication initiated by a one-ended double-strand break.

Axial element

A proteinaceous structure around which the chromosomes condense at the start of synapsis.

Lateral element

A structure in the synaptonemal complex that forms when a pair of sister chromatids condenses on to an axial element.

Central element

A structure that lies in the middle of the synaptonemal complex, along which the lateral elements of homologous chromosomes align.

Recombination nodules (nodes)

Dense objects present on the synaptonemal complex; they may represent protein complexes involved in crossing over.

Recombinase

Enzyme that catalyzes site-specific recombination.

Core sequence

The segment of DNA that is common to the attachment sites on both the phage lambda and bacterial genomes.