Our research interests are currently focused on a family of sugars called the sialic acids, and their roles in biology, evolution and disease. The surfaces of all cells in all organisms are decorated with a dense and complex array of sugar chains. These "glycans" are known to mediate or modulate many biological processes including sub-cellular and cellular trafficking, intercellular adhesion, signaling, and microbial attachment. Much data also indicates their involvement in embryonic development, normal tissue organization, tumor metastasis, and in the interactions of cells with extra-cellular molecules. We use tools of molecular biology, biochemistry, genetics and genomics to investigate selected areas of glycobiology. The present focus is on the sialic acids, which are found at the outermost position on the glycan chains of all vertebrate cell surfaces and glycoproteins. Currently active projects are relevant to the roles of sialic acids in viral and bacterial infectivity, the regulation of the immune response, the progression and spread of tumors and unique aspects of human brain evolution. We are particularly intrigued by finding multiple differences in sialic acid biology between humans and our closest evolutionary cousins, the great apes. These differences are a signature of the events that occurred during the last few million years of human evolution, and may be relevant to understanding several aspects of the current human brain, both in health and disease.