---
res:
  bibo_abstract:
  - Crosses between closely related species give two contrasting results. One result
    is that species hybrids may be inferior to their parents, for example, being less
    fertile [1]. The other is that F1 hybrids may display superior performance (heterosis),
    for example with increased vigour [2]. Although various hypotheses have been proposed
    to account for these two aspects of hybridisation, their biological basis is still
    poorly understood [3]. To gain further insights into this issue, we analysed the
    role that variation in gene expression may play. We took a conserved trait, flower
    asymmetry in Antirrhinum, and determined the extent to which the underlying regulatory
    genes varied in expression among closely related species. We show that expression
    of both genes analysed, CYC and RAD, varies significantly between species because
    of cis-acting differences. By making a quantitative genotype-phenotype map, using
    a range of mutant alleles, we demonstrate that the species lie on a plateau in
    gene expression-morphology space, so that the variation has no detectable phenotypic
    effect. However, phenotypic differences can be revealed by shifting genotypes
    off the plateau through genetic crosses. Our results can be readily explained
    if genomes are free to evolve within an effectively neutral zone in gene expression
    space. The consequences of this drift will be negligible for individual loci,
    but when multiple loci across the genome are considered, we show that the variation
    may have significant effects on phenotype and fitness, causing a significant drift
    load. By considering these consequences for various gene-expression-fitness landscapes,
    we conclude that F1 hybrids might be expected to show increased performance with
    regard to conserved traits, such as basic physiology, but reduced performance
    with regard to others. Thus, our study provides a new way of explaining how various
    aspects of hybrid performance may arise through natural variation in gene activity.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Ulises
      foaf_name: Rosas, Ulises
      foaf_surname: Rosas
  - foaf_Person:
      foaf_givenName: Nicholas H
      foaf_name: Barton, Nicholas H
      foaf_surname: Barton
      foaf_workInfoHomepage: http://www.librecat.org/personId=4880FE40-F248-11E8-B48F-1D18A9856A87
    orcid: 0000-0002-8548-5240
  - foaf_Person:
      foaf_givenName: Lucy
      foaf_name: Copsey, Lucy
      foaf_surname: Copsey
  - foaf_Person:
      foaf_givenName: Pierre
      foaf_name: Barbier De Reuille, Pierre
      foaf_surname: Barbier De Reuille
  - foaf_Person:
      foaf_givenName: Enrico
      foaf_name: Coen, Enrico
      foaf_surname: Coen
  bibo_doi: 10.1371/journal.pbio.1000429
  bibo_issue: '7'
  bibo_volume: 8
  dct_date: 2010^xs_gYear
  dct_identifier:
  - UT:000280557100013
  dct_language: eng
  dct_publisher: Public Library of Science@
  dct_title: Cryptic variation between species and the basis of hybrid performance@
...