Asymmetric viability of
reciprocal-cross hybrids between
crested and marbled newts (triturus
cristatus and t. marmoratus)

Arntzen, JW; Jehle, R; Bardacki, F; Burke, T; Wallis, GP

Abstract

Hybridization between divergent lineages often results in reduced hybrid viability. Here we report findings from a series of
independent molecular analyses over several seasons on four life stages of F1 hybrids between the newts Triturus cristatus and
T. marmoratus. These two species form a bimodal hybrid zone of broad overlap in France, with F1 hybrids making up about
4% of the adult population. We demonstrate strong asymmetry in the direction of the cross, with one class (cristatus-mothered)
making up about 90% of F1 hybrids. By analyzing embryos and hatchlings, we show that this asymmetry is not due to prezygotic
effects, as both classes of hybrid embryos are present at similar frequencies, implicating differential selection on the two hybrid
classes after hatching. Adult F1 hybrids show a weak Haldane effect overall, with a 72% excess of females. The rarer marmoratusmothered
class, however, consists entirely of males. The absence of females from this class of adult F1 hybrids is best explained
by an incompatibility between the cristatus X chromosome and marmoratus cytoplasm. It is thus important to distinguish the two
classes of reciprocal-cross hybrids before making general statements about whether Haldane’s rule is observed.

Citation

cristatus and t. marmoratus). Evolution, 63, 1191-1202. https://doi.org/10.1111/j.1558-5646.2009.00611.x

• Journal Article Type: Article
• Publication Date: Jan 1, 2009
• Deposit Date: Oct 30, 2009
• Journal: Evolution
• Print ISSN: 0014-3820
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 63
• Pages: 1191-1202
• DOI: https://doi.org/10.1111/j.1558-5646.2009.00611.x
• Keywords: Allozyme, Bateson–Dobzhansky–Muller incompatibility, cytonuclear incompatibility, hybridization, microsatellite,; mtDNA, postzygotic isolation asymmetry, Triturus
• Publisher URL: http://dx.doi.org/10.1111/j.1558-5646.2009.00611.x