GENE NUMBERS AND GENIC VARIABILITY INCIONA INTESTINALISANDBRANCHIOSTOMA LANCEOLATUM

Abstract

The number of genes coding for various enzymes have been determined in Ciona intestinalis (Tunicata) in comparison with Branchiostoma lanceolatum (Cephalochordata) using electrophoretic methods. Both species, generally, have identical gene numbers for homologous proteins. This finding does not support the hypothesis that Branchiostoma represents an anciently polyploid step relative to Ciona. High levels of allozymic variation were observed in the two species. The data are discussed in view of the neutral mutation hypothesis.