What "colors" of germplasm are available? Traditionally, especially for agriculture, germplasm has consisted of different races of the same species (or crop varieties), other species that were closely related to a crop, and even the wild version of a crop species. In fact, recently, finding wild sources of domesticated crops has become an important priority for agriculture for two primary reasons. First, the wild relatives of domesticated crops are becoming increasingly threatened by world development. Second, the wild relatives may still possess some interesting genes that were lost or omitted from early breeding attempts. After all, the nature of agriculture has changed dramatically since domestication began.

Plant breeders especially are renowned for taking ad-vantage of a wide variety of germplasm. Wheat, for example consists of germplasm from three or more separate species. In today’s world, germplasm for plant breeders has virtually no restriction: germplasm may be derived from bacteria, unrelated varieties of plant, animals, or even completely artificial "genes" through modern molecular techniques (also see "Genomics in Aquaculture" by Dr. Kimberly Reece).

For shellfish, breeders have largely limited themselves to the local race of a single species. In some cases, the same species from an-other region have been tested as well. There are no examples of long-term breeding efforts incorporating hybrids between two species– an approach once a corner stone of agricultural breeding techniques.

You can’t blame the shellfish breeders for their lack of sophistication. For one, aquaculture species, like shellfish, are wild, in the same state (genetically speaking) that their agricultural counterparts were thousands of years ago. Aquaculture breeders have been concentrating on the steps necessary for domestication, that is, adapting the wild species to the needs of aquaculture. Also, importation of other germplasm can be problematic. For instance, would oysters imported from the Gulf Coast transmit a different form of the parasite that causes Dermo-disease in native stocks? (Since there is some evidence that this can happen, we routinely quarantine imports.) The is-sue of germplasm from non-natives, that is, other species, is even more complicated. In addition to disease considerations, there are concerns of reproduction by the non-natives. Where do you put them so that reproduction is not a problem?

On the other hand, there is an immense resource of shellfish (or fish) germplasm available throughout the country and throughout the world that could provide interesting genes or gene combinations for our breeding efforts. How do we avail ourselves of these resources? ABC will be proposing to the legislature in 1999 a second round of funding to complete the funding begun in 1997. Our principal capital request will be for an aquaculture germplasm re-source (agpr) facility. As envisioned, the facility would consist of three components.

• The first is quarantine capabilities for holding non-native species (and thus their germplasm) over periods of generations, without fear of environmental consequence. Presently, we have little capacity for holding non-natives much past the seed stages of their life cycle. A flow through quarantine system would al-low ABC to exploit a full range of germplasm resources.

• The second feature of the proposed "agpr" facility is the capability to cryopreserve (deep freeze) and store gametes from important germplasm resources. Such resources might range from storage of gametes from our own select stocks for safekeeping, to non-native imports of gametes for hybrid trials (for ex-ample, from the Southern hemisphere), or to local valuable stocks that may be threatened with extinction. An example of the latter might be a local race of "super-oyster" from the Bay, such as the Tangier oysters that received so much attention recently.

• The final element of the "agpr" troika is the capability of DNA archiving. Deposits in this archive would be valuable DNA constructs, tissues from our own specially created shellfish families for mapping and other reference use, and, importantly, material from reference families from other labs, nationally and internationally. ABC has already taken on the role as national repository of such material, and completion of the "agpr" facility will be central to our role here.

In summary, the hues of our selective breeding will be partly dictated by the colors in our palette. In a perfect world, a genetics center should be unrestricted in its access to a rich variety of colors, and germplasm has everything to do the final outcome of our painting.

GENOTYPE

We casually divide the activities of ABC into two categories, loosely described as genotype and phenotype. By genotype we mean analysis of DNA and its organization on chromosomes. For example, genes are arrayed on chromosomes in a linear fashion. Geneticists can construct road maps locating these genes and in turn, this provides information on the overall organization of related groups of genes. At ABC, our molecular genetics group, headed by Dr. Kimberly Reece, is endeavoring to produce a map of the American oyster, Crassostrea virginica. A "medium density" genetic map of the oyster genome is one of ABC’s principal goals for the next several years. We collaborate directly with Dr. Patrick Gaffney at the University of Delaware’s College of Marine Studies. We also work in concert with a number of other investigators working on oyster genomics including Drs. Ximing Guo of Rutgers University, Dennis Hedgecock of Bodega Bay Marine Lab, and several international labs.

Genotype activities also include information about how oyster species are related and about how one species might or might not be subdivided into discreet populations. A good example of the usefulness of this information comes from our work with non-native species, specifically the Suminoe oyster, Crassostrea ariakensis (formerly C. rivularis). The Suminoe oyster is widely distributed throughout southeast Asia. I co-occurs with a number of other related, similar looking species. We at ABC are interested in learning more about the distribution of these species, what makes it distinct from other species, and how the different populations of Suminoe oyster – for example, one from southern China versus one from eastern India – differ from each other. The ABC molecular lab therefore has significant capabilities for population genetic analyses of these sorts.