Oyster Research and Restoration in U.S. Coastal Waters: Abstracts

two oyster shells - top one showing inside and bottom showing outside of the shell

Oyster Research and Restoration in U.S. Coastal Waters: Strategies for the Future

Abstracts
Workgroup: Genetics and Oyster Populations

Development of a moderate density linkage map of the eastern oyster Crassostrea virginica: Identification of disease resistance genes

Principal Investigator(s):

Patrick M. Gaffney, University of Delaware, pgaffney@udel.edu

Co-Investigator(s):

K. Reece, Virginia Institute of Marine Science

Funding Period: 2000

Microsatellite markers were designed from enriched genomic DNA libraries and a large random genomic DNA library. Primer sets have been designed to amplify 101 of 336 microsatellite loci identified; 32 amplified well, 19 were screened to detect polymorphisms; 8 have been tested for allelic transmission and Mendelian segregation in four families. Non-Mendelian genotypic proportions were often observed, attributable to null (non-amplifying) alleles and viability selection.

Non-microsatellite nuclear DNA marker development focused on expressed sequence tags (ESTs) and anonymous loci. We tested 32 primer sets and optimized 17 for screening of polymorphisms. Size polymorphisms were found at three intron loci, and restriction enzyme polymorphisms discovered in five loci.

IMPACTS and/or BENEFITS:
The DNA markers developed are being employed for several studies beyond construction of the genetic linkage map, including genetic tracking of oyster restoration projects with selected oyster stocks. In addition, these markers will be applied to high-resolution population genetic studies of natural oyster populations, in order to evaluate the natural distribution of germ plasm diversity.

PROJECT PUBLICATIONS:

Gaffney, P. M. 2001. Genomic approaches to marker development and mapping in the eastern oyster, Crassostrea virginica. pp. 84-91 in: (Shimizu, N. et al., ed.) Aquatic Genomics. Springer-Verlag, Tokyo.

Xu, Z., X. Guo, P. M. Gaffney, and J. C. Pierce. 2001. Chromosomal location of the major ribosomal RNA genes in Crassostrea virginica and Crassostrea gigas. Veliger 44:79-83.

Brown, B. L., D. E. Franklin, P. M. Gaffney, M. Hong, D. DenDanto, and I. Kornfield. 2000. Characterization of microsatellite loci in the eastern oyster, Crassostrea virginica. Molecular Ecology 9:2217-2219

W.L. Ribeiro, P.M. Gaffney, S.K. Allen, Jr., and K.S. Reece. Non-Mendelian segregation ratios and null alleles in microsatellite markers of the eastern oyster Crassostrea virginica. J. Shellfish Research (submitted)

UM-SG-TS-2003-01 www.mdsg.umd.edu

This publication was supported by funds from
the NOAA National Sea Grant College Program and the
Maryland and Virginia Sea Grant College Programs

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Abstracts Workgroup: Genetics and Oyster Populations

Development of a moderate density linkage map of the eastern oyster Crassostrea virginica: Identification of disease resistance genes

Abstracts
Workgroup: Genetics and Oyster Populations