Duplicated sporulation genes in bacteria Implications for simple developmental systems

AbstractStatistical analysis indicates that about 150 genes might be needed for spore formation in Bacillus subtilis [1]. We have sequenced 11 of these and examined the predicted amino acid sequences for the possibility that present-day sporulating bacteria may have evolved from ancestral forms in which sporulation was governed by a smaller number of genes. We have identified two pairs of duplicated genes. The first of them involves a sequence which shows major homologies with both the sigma factor (σ) of RNA polymerase in Escherichia coli and σ29 in B. subtilis. Another example of homology involves no less than 4 separate genes coding for the acid-soluble proteins of the spore [2]. We conclude that sporulation may have evolved from a much smaller number of genes that we first envisaged and it is likely, anyway, to be no more complex than replication of the larger coliphages