The use of gene conversion to study synaptinemal complex structure and molecular details of chromatid pairing in meiosis.

Gene conversion can be used to study: the topography and pairing relationships of the four chromatids of a bivalent at the time of crossing over and hybrid DNA formation, the lengths of intimately paired segments and the frequency of intimate pairing at particular sites. Conversion ratios of different types, corresponding-site interference, co-conversion, and the range and distribution of conversion frequencies are discussed in relation to DNA and chromatid pairing, and synaptinemal complex organisation. Conversion data from Ascobolus immersus and other fungi are compared with electron microscope data from various organisms and with models of the synaptinemal complex.