Genetics of the Lion-Paw Scallop (Nodipecten subnodosus) - Baja California Peninsula, Mexico

The lion-paw scallop is the largest scallop found in the Eastern Pacific and is distributed around the Baja California Peninsula, Mexico.  With high economic value, a great deal of interest exists in furthering the development of aquaculture. However, in doing so, native lion-paw scallop populations are being disturbed by human actions.  Along with Dr. Ana M. Ibarra of CIBNOR (La Paz, B.C.S., Mexico), microsatellite markers have been developed and are being applied for molecular analyses of the lion-paw scallop.  These analyses are being performed with the purpose of applying the data for conservation of natural populations of the species while also aiding in the development of successful aquaculture practices.

Looking toward the Gulf of California,
just south of Loreto, B.C.S. Mexico. 
It is in this area that an all-female coop-
erative is working to begin aquaculture
of the lion-paw scallop.

Question:  What is the genetic make-up of induced mass spawns of lion-paw scallop such as those used in aquaculture?            

    Results of this investigation are published in the July/Aug 2008 issue of the Journal of Heredity, where a photo of the lion-paw scallop
    is pictured on the journal cover.
    For a pdf of this paper, click on the abstract below.
 

Question:   What is the genetic relationship between and within naturally occurring populations of the lion-paw scallop?

Data collection is finalized and a manuscript is in preparation outlining the first investigation of population structure in this species.  The data show a great deal of gene flow within the Gulf of California, and significant population structure between coasts.  These results will act as baseline information for future monitoring of these natural populations.

Question:  Are aquaculture practices (induced spawning and grow-out in waters adjacent to native populations) impacting the natural genetic diversity of the species?

With no prior information about the extent of gene flow or larval dispersal between proximate populations, the possibility exists that introgression is occurring between scallops grown for aquaculture and local, wild populations.  Molecular techniques, such as microsatellite DNA genotyping allow for a comparison of genetic diversity within and between aquaculture and natural lion-paw scallop populations.  In addition to looking for signal of introgression between cultured and wild populations, this study also allows for an assessment of whether the scallops grown in aquaculture reflect the diversity of the wild populations from which they are derived.  The Lagoon Ojo de Liebre is the focus of this study, funded by UC MEXUS.  This lagoon is within the Vizcaino Biosphere Reserve and adjacent to the Lagoon Guerrero Negro, where aquaculture in taking place (map coming soon).

Question:  Are there areas of the genome associated with traits such as adductor muscle size, shell size, and shell color?

Microsatellite markers developed in our laboratory and AFLP are being employed to created a linkage map of the lion-paw scallop genome.  This linkage map will then be employed to search for QTL associated with growth traits in this species.  Our F1, initial mapping family is currently being harvested and F2 mapping families are being spawned.  This project is an exciting first step in moving toward marker assisted selection for aquaculture of this species.

Photo by Aldo Vargas-Mendieta (CIBNOR)

For more information, contact Jessica Petersen (jlpetersen@ucdavis.edu).