| Description | Slide shows a diagram of 'the evolutionary divergence of X and Y chromosomes, shown by the pachytene pairing and metaphase association, following two series according to the relative positions of centromeres and differential segments (white in X, black in Y).'
The diagram considers chromosomes of mammalia, drosophila melanogaster ps'obsc, lebistes, many plants, rumex, bryophyra, melandium, phragmatobia, hemiptera, nematoda, orthoptera and coleoptera.
Title below diagram reads: 'Fig. 22. The evolutionary divergence of X and Y chromosomes, shown by the pachytene pairing and metaphase association, following two series according to the relative positions of centromeres and differential segments (white in X, black in Y). Pairing segments hatched. The mammalian type corresponds to the unequal chromosomes illustrated in Fig. 5'. |