Combining TwoStage Testing and Interval Mapping S

Authors: D Lallias L GomezRaya C S Haley I Arzul S Heurtebise A R Beaumont P Boudry S Lapègue

Publish Date: 2009/01/14

Volume: 11, Issue: 5, Pages: 570-

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Abstract

We have identified quantitative trait loci QTL in the flat oyster Ostrea edulis for resistance to Bonamia ostreae a parasite responsible for the dramatic reduction in the aquaculture of this species An F2 family from a cross between a wild oyster and an individual from a family selected for resistance to bonamiosis was cultured with wild oysters injected with the parasite leading to 20 cumulative mortality Selective genotyping of 92 out of a total of 550 F2 progeny ie 46 heavily infected oysters that died and 46 parasitefree oysters that survived was performed using 20 microsatellites and 34 amplification fragment length polymorphism primer pairs Both a twostage testing strategy and QTL interval mapping methods were used The twostage detection strategy had a high power with a low rate of false positives and identified nine and six probable markers linked to genes of resistance and susceptibility respectively Parentspecific genetic linkage maps were built for the family spanning ten linkage groups n = 10 with an observed genome coverage of 69–84 Three QTL were identified by interval mapping in the first parental map and two in the second Good concordance was observed between the results obtained after the twostage testing strategy and QTL mappingThis research has been financed by the European Regional Development Fund INTERREG IIIB project 091–AAAG and received the support of the Marine Genomics Europe Network of Excellence through a 1month fellowship Gender Action Plan The authors thank Sylvie Ferrand Bruno Chollet Maeva Robert and Benjamin Morga for their help and involvement during the cohabitation challenge experiment CSH acknowledges support from the Biotechnology and Biological Sciences Research Council The authors thank two anonymous referees for constructive comments on the manuscriptTransmission parameter v Ss×ss corresponds to segregation 11 whereas transmission parameter v Ss×Ss corresponds to segregation 31 The probability of Nx or more individuals inheriting the given marker allele under ν is the power of the test P textTDT = int zinfty fleft x rightdx where fx is the normal density with z = fracfracn + 196sqrt n 2 nnu sqrt nnu left 1 nu right and z = fracfrac3n + 196sqrt 3n 4 nnu sqrt nnu left 1 nu right for mating with segregation types 11 and 31 respectively

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