Development Shapes a Consistent Inbreeding Effect in Mouse Crania of Different Line Crosses. Issue 8 (18th January 2017)

• Record Type: Journal Article
• Authors: Pavličev, Mihaela; Mitteroecker, Philipp; Gonzalez, Paula M.; Rolian, Campbell; Jamniczky, Heather; Villena, Fernando Pardo‐Manuel; Marcucio, Ralph; Spritz, Richard; Hallgrimsson, Benedikt
• Is Part Of: Journal of experimental zoology. Volume 326:Issue 8(2016)
• Page Start: 474
• Page End: 488
• Publication Date: 2017-01-18
• Subjects: Developmental biology -- Periodicals; Evolution (Biology) -- Periodicals; Molecular evolution -- Periodicals; Zoology -- Periodicals; Evolution, Molecular -- Periodicals; Developmental Biology -- Periodicals; Zoology -- Periodicals; 591
• DOI: 10.1002/jez.b.22722
• Languages: English
• ISSNs: 1552-5007

Abstract

GRAPHICAL ABSTRACT: We investigated the pattern of variation in mouse cranial traits of a diallel cross of eight inbred lines. We find that the mice originating from crosses of differently selected inbred mouse strains deviate from the expected intermediate form in a consistent phenotypic direction, regardless of genetic background, i.e. the parental strains. We suggest that this non‐uniform, non‐additive pattern of variation is a signature of developmental constraint, and reveals the effect of inbreeding. Abstract: Development translates genetic variation into a multivariate pattern of phenotypic variation, distributing it among traits in a nonuniform manner. As developmental processes are largely shared within species, this suggests that heritable phenotypic variation will be patterned similarly, in spite of the different segregating alleles. To investigate developmental effect on the variational pattern in the shape of the mouse skull across genetically differentiated lines, we employed the full set of reciprocal crosses (a.k.a. diallel) between eight inbred mouse strains of the Collaborative Cross Project. We used geometric morphometrics and multivariate analysis to capture cranial size and shape changes in 8 parentals and their 54 F1 crosses. The high heterozygosity generated in the F1 crosses allowed us to compare the multivariate deviations of the F1 phenotypes from the expected midparental phenotypes in different haplotype combinations. In contrast to body weight, we found a high degree of nonadditive deviation in craniofacial shape. Whereas the phenotypic and genetic divergence of parental strains manifested in high dimensionality of additive effects, the nonadditive deviations exhibited lesser dimensionality and in particular a strikingly coherent direction in shape space. We interpret this finding as evidence for a strong structuring effect of a relatively small set of developmental processes on the mapping of genetic to phenotypic variation.