PHYLOGENETIC CONSERVATION OF GANGLIOSIDE GD3 EXPRESSION DURING EARLY VERTEBRATE ONTOGENY

Gangliosides were investigated in adult brains and in 5-vesicle stage embryos of representatives belonging to the four vertebrate classes: C hondrichthyes, Amphibia, Aves and Mammalia. Considerable variability i n brain ganglioside composition and concentration was observed among t he adult vertebrates. The ganglioside patterns of the developmentally matched vertebrate embryos were similar in that each comprised GD3 as the predominant ganglioside. The phylogenetic conservation of abundant GD3 expression during early vertebrate ontogeny is interpreted as bio chemical evidence consistent with van Baer's theory of increasing diff erentiation and suggests that GD3 is of critical importance for normal vertebrate development.