The Origin and Behaviour of Chiasmata. XIV

Cytological Studies on Dipnoi, Urodela, Anura, and Emys

“…On the other hand, a negative correlation does not account for the peculiar localization of the chiasmata: in that case it would .be very strange if chiasmata were almost always formed in the short arm. The lack of correlation in this respect between the two arms of a chromosome has previously been observed in Drosophila (MATHER, 1936), Fritillaria (BENNETT, 1938), and Uvularia (BARBER, 1941), whilst the reverse has been found in other species of Fritillaria (DARLINGTON, 1937;FRANKEL, 1940), as well as in Culex and Dicraniomya (PXTAU, 1941).…”

“…The higher chromosome numbers, found among the more primitive forms, seem to point to »fusions» as an active factor in the phylogeny. (10) The meiosis in these forms is quite normal. (11) The zygotene-pachytene stages are characterized by a marked polarization of all the chromosome ends.…”

“…. VI -a pair of middlesized chromosomes with arms of equal length ... VII, VIII, IX and X four pairs of chromosomes with arms markedly differing in length ... XI and XII -two pairs of small chromosomes with arms of unequal length ... ». In this description PROKOFIEWA apparently includes five of pairs 1-6, one of pairs [7][8] and pairs [9][10][11][12][13][14] (cf, p. 248). Thus interpreted, her results correspond rather well with PARMENTER'S findings and my own.…”