The synaptonemal complex isolated from the spermatocyte nuclei by exhaustive hydrolysis of the latter by
DNase II contains tightly associated DNA sequences (
SCAR DNA). Here we studied the compositional properties of a cloned family of
SCAR DNA of golden hamster, namely we performed the localization of 27
SCAR DNA clones on compositionally fractionated genomic
DNA from golden hamster. We observed that sequences of the
SCAR DNA family are mainly localized in the GC-poor
isochore families L1 and L2, that showed 63% hybridization signals. This means that 37% of signals is referred to the GC-rich
isochores, indicating the presence of
SCAR DNA overall the genome, even if each
isochore family presents differences in density and sequence type. Moreover, the
SCAR DNA sequences containing regions of homology with LINE/SINE repeats were observed in all the
isochore families. The compositional localization of
SCAR DNA is in agreement with the hypothesis that SC and
SCAR DNA participate in the
chromatin organization during the meiosis prophase I, which should result in the attachment of
chromatin loops to lateral elements of SC along the whole length of the latter.