Answer to Question #60699 in Molecular Biology for Sanjukta Ghosh

Question

How is early recombination nodule different from late recombination nodule (structurally and functionally)?

Answer 1

Early recombination nodules appear at leptotene and persist into early pachytene of meiosis. Late recombination nodules appear in pachytene and remain into early diplotene.
Two types of recombination nodules (early and late) are distinguished by shape and size, relative numbers, and association with unsynapsed and/or synapsed chromosomal segments. For example, in plants, early recombination nodules are protein complexes, 100 nm in diameter, that are associated with forming synaptonemal complexes during leptotene and zygotene. Early recombination nodules are more variable in size and shape and 2 to 20 times more numerous per unit length of synaptonemal complex than late recombination nodules (Anderson at all, 2001). But late recombination nodules sizes are more complicated than early ones.
The function of early recombination nodules is not clear, but they may have a role in searching for DNA homology, synapsis, gene conversion and/or crossing over. Late recombination nodules are well correlated with crossing over