Albinism in phylogenetically and geographically distinct populations of Astyanax cavefish arises through the same loss-of-function Oca2 allele

Gross, Joshua B.; Wilkens, Horst

doi:10.1038/hdy.2013.26

Cited by 54 publications

(51 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We characterized biological functions associated with differentially expressed genes across four stages of development. We tested several thresholds (see Methods section); however, the top 2.5% of over‐ and underexpressed genes included those with morphological and/or behavioral relevance, and provided a manageable number of genes for further analysis (Stricker and Jeffery, ; Gross et al., ). GO enrichment analyses (Fig.…”

Section: Resultsmentioning

confidence: 99%

A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations

Stahl

Gross

2017

J Exp Zool Pt B

View full text Add to dashboard Cite

Organisms that are isolated into extreme environments often evolve extreme phenotypes. However, global patterns of dynamic gene expression changes that accompany dramatic environmental changes remain largely unknown. The blind Mexican cavefish, Astyanax mexicanus, has evolved an number of severe cave-associated phenotypes including loss of vision and pigmentation, craniofacial bone fusions, increased fat storage, reduced sleep and amplified non-visual sensory systems. Interestingly, surface-dwelling forms have repeatedly entered different caves throughout Mexico, providing a natural set of “replicate” instances of cave isolation. These surrogate “ancestral” surface-dwelling forms persist in nearby rivers, enabling direct comparisons to the “derived” cave-dwelling form. We evaluated changes associated with subterranean isolation by measuring differential gene expression in two geographically distinct cave-dwelling populations (Pachón and Tinaja). To understand the impact of these expression changes on development, we performed RNA-sequencing across four critical stages during which troglomorphic traits first appear in cavefish embryos. Gene ontology (GO) studies revealed similar functional profiles evolved in both independent cave lineages. However, enrichment studies indicated that similar GO profiles were occasionally mediated by different genes. Certain “master” regulators, such as Otx2 and Mitf, appear to be important loci for cave adaptation, as remarkably similar patterns of expression were identified in both independent cave lineages. This work reveals that adaptation to an extreme environment, in two distinct cavefish lineages, evolves through a combination of unique and shared gene expression patterns. Shared expression profiles reflect common environmental pressures, while unique expression likely reflects the fact that similar adaptive traits evolve through diverse genetic mechanisms.

show abstract

Section: Resultsmentioning

confidence: 99%

A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations

Stahl

Gross

2017

J Exp Zool Pt B

View full text Add to dashboard Cite

show abstract

“…Inference in ecological genomics will thus benefit strongly from the integration of multiple complementary analytical approaches (e.g., source-derived vs. derived-derived comparisons, delta divergence, genealogical sorting; see also Grossman et al 2010), requiring extensive population-level replication within a clear-cut ecological context. On the bright side, genome scans specifically looking for the signature described in our study might help discover adaptation genes in empirical systems where ecological divergence is likely to have occurred repeatedly by re-cycling genetic variation (e.g., Terai et al 2006; Renaut et al 2011; Tennessen & Akey 2011; Domingues et al 2012; Nadeau et al 2012; Gross & Wilkens 2013; Streisfeld et al 2013). …”

Section: Discussionmentioning

confidence: 99%

The genomic signature of parallel adaptation from shared genetic variation

et al. 2014

View full text Add to dashboard Cite

Parallel adaptation is common and may often occur from shared genetic variation, but the genomic consequences of this process remain poorly understood. We first use individual-based simulations to demonstrate that comparisons among populations adapted in parallel from shared variation reveal a characteristic genomic signature around a selected locus: a low divergence valley centered at the locus and flanked by twin peaks of high divergence. This signature is initiated by the hitchhiking of haplotype tracts differing among derived populations in the broader neighborhood of the selected locus (driving the high divergence twin peaks) and shared haplotype tracts in the tight neighborhood of the locus (driving the low divergence valley). This initial hitchhiking signature is reinforced over time because the selected locus acts as a barrier to gene flow from the source to the derived populations, thus promoting divergence by drift in its close neighborhood. We next empirically confirm the peak-valley-peak signature by combining targeted and RAD sequence data at three candidate adaptation genes in multiple marine (source) and freshwater (derived) populations of threespine stickleback. Finally, we use a genome-wide screen for the peak-valley-peak signature to discover additional genome regions involved in parallel marine-freshwater divergence. Our findings offer a new explanation for heterogeneous genomic divergence and thus challenge the standard view that peaks in population divergence harbor divergently selected loci, and that low-divergence regions result from balancing selection or localized introgression. We anticipate that genome scans for peak-valley-peak divergence signatures will promote the discovery of adaptation genes in other organisms.

show abstract

“…Morphological and behavioral analyses have identified dimorphisms associated with parallel evolution in different cavefish populations (Gross and Wilkens, 2013;Jeffery, 2009). Of the five cavefish populations assayed for sleep, all exhibited reduced sleep compared with surface fish.…”

Section: Mechanistic Differences In Sleep Loss Between Cavefish Populmentioning

confidence: 99%

The lateral line confers evolutionarily derived sleep loss in the Mexican cavefish

Jaggard

Robinson

Stahl

et al. 2017

Journal of Experimental Biology

View full text Add to dashboard Cite

Sleep is an essential behavior exhibited by nearly all animals, and disruption of this process is associated with an array of physiological and behavioral deficits. Sleep is defined by changes in sensory gating that reduce sensory input to the brain, but little is known about the neural basis for interactions between sleep and sensory processing. Blind Mexican cavefish comprise an extant surface dwelling form and 29 cave morphs that have independently evolved increased numbers of mechanoreceptive lateral line neuromasts and convergent evolution of sleep loss. Ablation of the lateral line enhanced sleep in the Pachoń cavefish population, suggesting that heightened sensory input underlies evolutionarily derived sleep loss. Targeted lateral line ablation and behavioral analysis localized the wake-promoting neuromasts in Pachoń cavefish to superficial neuromasts of the trunk and cranial regions. Strikingly, lateral line ablation did not affect sleep in four other cavefish populations, suggesting that distinct neural mechanisms regulate the evolution of sleep loss in independently derived cavefish populations. Cavefish are subject to seasonal changes in food availability, raising the possibility that sensory modulation of sleep is influenced by metabolic state. We found that starvation promotes sleep in Pachoń cavefish, and is not enhanced by lateral line ablation, suggesting that functional interactions occur between sensory and metabolic regulation of sleep. Taken together, these findings support a model where sensory processing contributes to evolutionarily derived changes in sleep that are modulated in accordance with food availability.

show abstract

Albinism in phylogenetically and geographically distinct populations of Astyanax cavefish arises through the same loss-of-function Oca2 allele

Cited by 54 publications

References 35 publications

A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations

A Comparative Transcriptomic Analysis of Development in Two Astyanax Cavefish Populations

The genomic signature of parallel adaptation from shared genetic variation

The lateral line confers evolutionarily derived sleep loss in the Mexican cavefish

Contact Info

Product

Resources

About