DOI: 10.5061/dryad.qk738
title: Data from: Constraint and opportunity: the genetic basis and evolution of modularity in the cichlid mandible

description: Modular variation, whereby the relative degree of connectivity varies
 within a system, is sometimes thought to evolve through natural selection.
 In this way, modularity may facilitate evolution. Alternatively, conserved
 patterns of modularity may act to constrain evolution by preventing
 certain functions from evolving. A comprehensive understanding of the
 interplay between these phenomena will require knowledge of both the
 inheritance and genetic basis of modularity. Here we explore these ideas
 in the cichlid mandible by investigating modularity at the genus, species,
 and through a new approach, the individual level. Specifically, we
 assessed patterns of covariation in Lake Malawi cichlid species that
 employ alternate 'biting' and 'suction-feeding' modes
 of feeding, and in a hybrid cross between these two ecotypes. Across the
 suction-feeding genus, patterns of modularity were conserved and reflected
 function. In contrast, the 'biting' species displayed a pattern
 of modularity that closely matched developmental modules. The modularity
 pattern present in our F2 population was similar to the pattern exhibited
 by our biter, suggesting a role for dominance. We also demonstrated that
 our individual-level metrics of modularity (IMM) were a valid quantitative
 traits and used them to map modularity QTL. In all, our findings suggest
 that modularity is both a constraining and evolvable force in cichlid
 evolution, with distinct patterns between species and variation among
 individuals.
description: Labeotropheus
 fuelleborniStandardizedLandmark and
 semilandmark data for Labeotropheus mandibles. This data had been
 superimposed together with data from Metriaclima zebra, and their F2
 hybrids. Size effects have been minimized/standardized for Labeotropheus
 separately using a multiple regression (see Standard6 in the IMP suite of
 software). Data is in IMP format with the last column on the right
 representing centroid size. The 30 columns left of centroid size represent
 the xy coordinates of regular landmarks.metriaclimaZebraStandardizedLandmark and semilandmark data for Metriaclima mandibles. This data had been superimposed together with data from Labeotropheus, and their F2 hybrids. Size effects have been minimized/standardized for Labeotropheus separately using a multiple regression (see Standard6 in the IMP suite of software). Data is in IMP format with the last column on the right representing centroid size. The 30 columns left of centroid size represent the xy coordinates of regular landmarks.standardizedF2sLandmark and semilandmark data for F2 hybrids. This data had been superimposed together with data from Metriaclima zebra,and Labeotropheus. Size effects have been minimized/standardized for each of F2 Labeotrophues and Metriaclima separately using a multiple regression (see Standard6 in the IMP suite of software). Data is in IMP format with the last column on the right representing centroid size. The 30 columns left of centroid size represent the xy coordinates of regular landmarks.