BEHAVIOR OF NA+ K+-ATPASE ALPHA-SUBUNIT ALLELES IN SEA-URCHIN EGGS UPON FERTILIZATION/

The allelic division of the Na+/K+-ATPase alpha-subunit gene was found in eggs of the sea urchin Hemicentrotus pulcherrimus by polymerase ch ain reaction (PCR). Two PCR products of different lengths were detecte d from a genome in one embryo derived from a fertilized egg, although only one product in one embryo derived from an artificially activated egg by parthenogenesis was detected, indicating one copy of the gene i n a haploid genome. One of the two PCR products from each fertilized e gg was identical in size to the product from an artificially activated egg in the same batch. The other PCR product was the same in length a s one of the products from the sperm with which the eggs were fertiliz ed. These results indicate that recombination of the heteromeric allel es of the Na+/K+-ATPase alpha-subunit gene occurs in the sea urchin eg g due to meiosis and fertilization. The sequencing of these products d emonstrated that their exon sequences were identical and that the intr on, inserted in the PCR products, generated polymorphism in length due to the frequency of the repeating 53 bp sequence and insertion/deleti on of other two segments.