Success of embryonic development in Xenopus haploids, hybrids, and cybrids.

n, number of different male-female combinations from which the results were added.†, unfertilized eggs and embryos that showed an abnormal or incomplete first cleavage were excluded from this analysis.‡, cross-fertilization efficiency was very low (∼3% in the best cases) for X. laevis sperm on X. tropicalis eggs; our attempts at cross-fertilizing UVed X. tropicalis eggs with X. laevis sperm were unsuccessful.