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Article
The Genetic Basis of Baculum Size and Shape Variation in Mice
G3: Genes | Genomics | Genetics
  • Nicholas G Schultz, University of Southern California
  • Jesse Ingels, University of Tennessee Health Science Center
  • Andrew Hillhouse, Texas A & M
  • Keegan Wardwell, The Jackson Laboratory
  • Peter L. Chang, University of Southern California
  • James M Cheverud, Loyola University Chicago
  • Cathleen Lutz, The Jackson Laboratory
  • Lu Lu, University of Tennessee Health Science Center
  • Robert W. Williams, University of Tennessee Health Science Center
  • Matthew D. Dean, University of Southern California
Document Type
Article
Publication Date
5-1-2016
Pages
1141-1151
Disciplines
Abstract

The rapid divergence of male genitalia is a preeminent evolutionary pattern. This rapid divergence is especially striking in the baculum, a bone that occurs in the penis of many mammalian species. Closely related species often display diverse baculum morphology where no other morphological differences can be discerned. While this fundamental pattern of evolution has been appreciated at the level of gross morphology, nearly nothing is known about the genetic basis of size and shape divergence. Quantifying the genetic basis of baculum size and shape variation has been difficult because these structures generally lack obvious landmarks, so comparing them in three dimensions is not straightforward. Here, we develop a novel morphometric approach to quantify size and shape variation from three-dimensional micro-CT scans taken from 369 bacula, representing 75 distinct strains of the BXD family of mice. We identify two quantitative trait loci (QTL) that explain ∼50% of the variance in baculum size, and a third QTL that explains more than 20% of the variance in shape. Together, our study demonstrates that baculum morphology may diverge relatively easily, with mutations at a few loci of large effect that independently modulate size and shape. Based on a combination of bioinformatic investigations and new data on RNA expression, we prioritized these QTL to 16 candidate genes, which have hypothesized roles in bone morphogenesis and may enable future genetic manipulation of baculum morphology.

Comments

Author Posting © Schultz et al, 2016. This article is posted here by permission of the Genetics Society of America for personal use, not for redistribution. The article was published in G3: Genes | Genomics | Genetics, Vol. 6, Iss. 5, May 2016, http://dx.doi.org/10.1534/g3.116.027888

Creative Commons License
Creative Commons Attribution 4.0
Citation Information
Nicholas G Schultz, Jesse Ingels, Andrew Hillhouse, Keegan Wardwell, et al.. "The Genetic Basis of Baculum Size and Shape Variation in Mice" G3: Genes | Genomics | Genetics Vol. 6 Iss. 5 (2016)
Available at: http://works.bepress.com/lu-lu/39/