DOI: 10.5061/dryad.6fm12
title: Data from: Fine-scale temporal analysis of genotype-dependent mortality at settlement in the Pacific oyster Crassostrea gigas

description: Settlement and metamorphosis mark a critical transition in the life cycle
 of marine invertebrates, during which substantial mortality occurs in both
 field and laboratory settings. Previous pair-crossing experiments with the
 Pacific oyster Crassostrea gigas have revealed significant selective or
 genotype-dependent mortality around the metamorphic transition, but the
 fine-scale nature and timing of this mortality is not known, particularly
 whether it occurs before, during or after metamorphosis. In this
 laboratory study, microsatellite marker segregation ratios were followed
 daily throughout the settlement and metamorphosis of an F2 cross of the
 Pacific oyster to examine the fine-scale patterns of genotype dependent
 mortality at this transition and whether settlement timing (early vs.
 late) might be under genetic control and affect inference of genotype
 dependent mortality. Settlement occurred over nine days (day 18 to day 27
 post-fertilization) with 68% of individuals settling either early (day 19)
 or late (day 24). Tracking the survival of spat for 40 days after initial
 settlement revealed almost no mortality and thus no appreciable genetic
 mortality. Temporal genetic analysis revealed that 3/11 loci exhibited
 genotype dependent mortality around the metamorphic transition, one of
 which (Cg205) was followed throughout settlement and metamorphosis.
 Alternative temporal patterns of strong selection against each homozygous
 genotype at Cg205 revealed possible defects in both the competency pathway
 (inability to initiate metamorphosis) and the morphogenesis pathway
 (mortality during the metamorphic transition). Quantitative trait locus
 (QTL) mapping of settlement timing identified three individual and one
 epistatic QTL with significant genetic effects on this trait (29% of the
 variance explained in total); however, two of these loci were linked to
 markers exhibiting selective mortality at metamorphosis, potentially
 confounding their apparent association with settlement timing. Overall,
 the results of this study highlight the complex nature of mortality and
 behavior during settlement and metamorphosis in oysters and suggest that
 endogenous sources of mortality at settlement may play an important role
 in the recruitment dynamics of oysters and possibly other broadcast
 spawning marine invertebrates.
description: Genotype Data for oyster
 spat (C. gigas) from early and late settlementThis excel sheet
 contains microsatellite marker genotypes for oyster spat settling on day
 19 or day 24. Genotypes were called by eye (and compared to parent
 genotypes) on a ABI 377 prism instrument using the Genescan software.
 These data form the basis of the QTL mapping analyses and chi-square
 comparisons of early vs. late settlement in Plough 2018. Column A contains
 the individual Spat ID, and columns C through BK contain the genotype
 data. Microsatellite marker names are prefixed by "Cg" and are
 presented in pairs of columns for each marker: one for spat settling on
 day 19, the other for day 24 (Row 1). Row 2 contains the cross-type of the
 parents (e.g. abxab) and Row 3 contains the C. gigas linkage group (LG)
 information for a given marker (LGs 1-10).Plough JEMBE Spat genotype data
 DRYAD.xlsx