Current and historical hybridization with differential introgression among three species of cyprinid fishes (genus Cyprinella)

Abstract

Hybridization is common among freshwater fishes, particular among the Cyprinidae. We used two mitochondrial genes and one nuclear gene to characterize hybridization among two species pairs of Cyprinella in southwestern North America. Genalogical patterns revealed that C. lutrensis and C. venusta are currently hybridizing in several localities producing apparent F(1), F(2) and backcross generations, yet there was no evidence for introgression outside of local hybrid zones. Alternatively, mitochondrial haplotypes from C. lutrensis appear to have introgressed into a C. lepida population in the Nueces River completely replacing the native C. lepida haplotype. There was no evidence of introgression of nuclear DNA and there does not appear to be ongoing hybridization. The population of C. lepida from the nearby Frio River exhibits no evidence of hybridization with C. lutrensis. Thus, contact between C. lutrensis and C. venusta results in the formation of localized hybrid swarms, while contact between C. lutrensis and C. lepida has resulted in complete mitochondrial introgression in the Nueces River or no apparent hybridization in the Frio River. The three different outcomes of contact between these species illustrate the variable nature of interspecific reproductive interactions and provide an excellent system in which to better understand the factors influencing hybridization among freshwater fishes.

Introgressive hybridization as a promoter of genome reshuffling in natural homoploid fish hybrids (Cyprinidae, Leuciscinae)

“…Similarly, AOL-like morphotypes are strikingly more evident at first sight than PDU-or PPO-like morphotypes, owing to the detection of a corneous lower lip otherwise absent in Achondrostoma sp. These results seem conflicting with previous works on hybridizing cyprinids where distinct HZs represented different outcomes of independent hybridization processes (Costedoat et al, 2007;Aboim et al, 2010;Broughton et al, 2011), which means that either the environmental pressure is identical in the HZs considered here (unlikely) or that the endogenous (genetic) selection forces are in fact the strongest in action.…”

“…The extent of hybridization Hybridization may have multiple effects at different stages and spatial contexts (Gerber et al, 2001;Costedoat et al, 2007;Broughton et al, 2011;Abbott et al, 2013). The already surveyed HZs of AOL Â PDU seem to behave differently (Aboim et al, 2010) with character displacement happening towards one or the other parental species (Collares- Pereira and Coelho, 1983;Gante et al, 2004;Aboim et al, 2010).…”

“…In this case study, ecological barriers between hybrids and parental species might be altered and/or degraded, so that gene flow back to pure species never actually ceases. However, the ultimate consequences of such apparently extensive and recurrent events to these populations and species remain unknown, and the probability of fixation of the resulting rearrangements depends on the demography of the hybrid swarms (Gerber et al, 2001;Seehausen, 2004;Costedoat et al, 2007;Broughton et al, 2011;Abbott et al, 2013). Usually disregarded (reviewed in Costedoat et al, 2007), these interactions might ultimately result in speciation or extinction faster than expected.…”

“…Natural introgression is commonly found among freshwater fishes, particularly in Cyprinidae (Scribner et al, 2001), where several cases have been comprehensively evaluated (Gerber et al, 2001;Costedoat et al, 2007;Aboim et al, 2010;Broughton et al, 2011). The different outcomes witnessed (reviewed in Abbott et al, 2013) reinforce the opportunity of using cyprinid fish to search for genomic signatures of hybridization.…”

Phylogeography and population genetics of Australian freshwater rainbowfishes

“…Many examples of hybridization between closely related taxa have been reported after anthropogenic introductions of otherwise allopatric populations of fishes (estimated to be around 50% in cases of hybridization reported in North American freshwater fishes in a review by SCRIBNER et al (2000). Evidence for hybridization in natural populations of freshwater fishes however, continues to increase, with many examples reported in Cyprinid carps and minnows (ALVES et al 2001;ABOIM et al 2010;BROUGHTON et al 2011), barbels (LAJBNER et al 2009GANTE et al 2015), and African cichlids (SALZBURGER et al 2002) to name just a few.…”