A developmental analysis of the histone patterns of two species of Xenopus and their hybrids

The histone patterns in Xenopus laevis and X. borealis have been examined at various developmental stages using acid-urea polyacrylamide electrophoresis. Qualitative differences between the two species have been demonstrated in the H1 fraction. These differences are not affected by alkaline phosphatase digestion. Quantitative changes during development in both H1 and H4 fractions have also been observed. In addition, histones from hybrids of the two species have been examined. H1 histones characteristic of both species are present by the neurula stage in laevis ♀ × borealis ♂ hybrids. Quantitative changes observed in borealis development are mimicked in laevis ♀ × borealis ♂ hybrid development.