Identification of Sturgeon Caviar Using DNA Markers

Abstract

The meat and, above all, the caviar from sturgeons have been gastronomic emblems of delicacy from time immemorial. When sturgeons were abundant, caviar was marketed primarily from three species (Huso huso, Acipenser gueldenstaedtii and A. stellatus) mostly from the Caspian Sea. However, these are not the only species of sturgeons used traditionally to produce quality caviar, nor is the Caspian its only geographic origin. For example, caviar from sturgeons belonging to the species A. sturio or A. naccarii captured in the Guadalquivir River (southern Spain) gained renown in the 1960s, winning prizes at world fairs. Now, when sturgeons are almost disappearing all over the world, the caviar trade has become far more complex. In fact, practically all sturgeon species can produce quality caviar, not only in the wild (in steady decline) but also in fish farms. This scenario makes it necessary to monitor the sale of caviar at a worldwide level, and for this the application of molecular techniques based on DNA, together with others, can be of great use. In this chapter, we present two types of DNA markers for this purpose: some, especially nuclear-DNA markers, indicate qualitative differences between the different species (presence/absence of these markers); and others, particularly mitochondrial-DNA, indicate differences in certain bases of nucleotide sequences. In addition, sturgeons produce interspecific hybrids. Consequently, nuclear markers along with mitochondrial ones are needed for accurately identifying the species responsible for a given caviar.