Sympatric speciation of spiny mice, Acomys , unfolded transcriptomically at Evolution Canyon, Israel

Abstract

Spiny mice, Acomys cahirinus, colonized Israel 30,000 y ago from dry tropical Africa and inhabited rocky habitats across Israel. Earlier, we had shown by mtDNA that A. cahirinus incipiently sympatrically speciates at Evolution Canyon I (EC I) in Mount Carmel, Israel because of microclimatic interslope divergence. The EC I microsite consists of a dry and hot savannoid "African" slope (AS) and an abutting humid and cool-forested "European" slope (ES). Here, we substantiate incipient SS in A. cahirinus at EC I based on the entire transcriptome, showing that multiple slope-specific adaptive complexes across the transcriptome result in two divergent clusters. Tajima's D distribution of the abutting Acomys interslope populations shows that the ES population is under stronger positive selection, whereas the AS population is under balancing selection, harboring higher genetic polymorphisms. Considerable sites of the two populations were differentiated with a coefficient of F ST = 0.25-0.75. Remarkably, 24 and 37 putatively adaptively selected genes were detected in the AS and ES populations, respectively. The AS genes involved DNA repair, growth arrest, neural cell differentiation, and heat-shock proteins adapting to the local AS stresses of high solar radiation, drought, and high temperature. In contrast, the ES genes involved high ATP associated with energetics stress. The sharp ecological interslope divergence led to strong slope-specific selection overruling the interslope gene flow. Earlier tests suggested slope-specific mate choice. Habitat interslope-adaptive selection across the transcriptome and mate choice substantiate sympatric speciation (SS), suggesting its prevalence at EC I and commonality in nature.adaptive ecological speciation | microclimate | natural selection | RNA-seq

Geographic contrasts between pre‐ and postzygotic barriers are consistent with reinforcement inHeliconiusbutterflies

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Population Genomics Reveals Speciation and Introgression between Brown Norway Rats and Their Sibling Species

“…A fundamental goal in evolutionary biology is to elucidate the interaction between adaptation and speciation in generating biological diversity ( Wolf et al 2010 ; Fitzpatrick et al 2015 ). Although, in the past few years, genetic or genomic variations to explain adaptation and speciation have been reported in a few animal cases ( Coyne and Orr 2004 ; Noor and Feder 2006 ; Schluter 2009 ; Li et al 2015 ; Li et al 2016 ; Marques et al 2016 ; Martinez Barrio et al 2016 ), we are still far from deciphering the genomic basis underlying these two processes ( Henning and Meyer 2014 ).…”

Range‐constrained co‐occurrence simulation reveals little niche partitioning among rock‐dwelling Montenegrina land snails (Gastropoda: Clausiliidae)

“…Radiations in ancient lakes are prime examples of such "strong" adaptations (Sch€ on & Martens, 2004). The majority of speciation events is allopatric (Coyne & Orr, 2004;Turelli, Barton, & Coyne, 2001), but an increasing number of studies suggests that sympatric speciation, when ranges of sister taxa overlap, is probably less exceptional than previously thought (Bolnick & Fitzpatrick, 2007;Li et al, 2016). In allopatry, sister taxa possess non-overlapping distribution areas, and their genetic differentiation follows geographical partitioning of the ancestral species' original range.…”