Figure 1

Chromosomal painting using derived probes of a highly heterochromatic and degenerated W chromosome from the amazonian pit viper (Bothrops atrox). The W probes (BaW) was used on the B. atrox chromosome spreads as control, showing large hybridized segments on the W chromosome. In the Boa constrictor, the BaW probe showed signals on the 7th pair. ISIS software was used for microphotography and analyzing images.