How could fully scaled carps appear in natural waters in Madagascar?

The capacity of organisms to rapidly evolve in response to environmental changes is a key feature of evolution, and studying mutation compensation is a way to evaluate whether alternative routes of evolution are possible or not. Common carps (Cyprinus carpio) carrying a homozygous loss-of-function mutation for the scale cover gene fgfr1a1, causing the 'mirror' reduced scale cover, were introduced in Madagascar a century ago. Here we show that carps in Malagasy natural waters are now predominantly covered with scales, though they still all carry the homozygous mutation. We also reveal that the number of scales in mutated carps is under strong polygenic genetic control, with a heritability of 0.49. As a whole, our results suggest that carps submitted to natural selection could evolve a wild-type-like scale cover in less than 40 generations from standing polygenic genetic variation, confirming similar findings mainly retrieved from model organisms.

Normal nasal cavity and paranasal sinuses in brown lemurs Eulemur fulvus: computed tomography and cross-sectional anatomy.

BACKGROUND: Far less is known about the normal anatomy of the nasal cavity of Eulemur fulvus; no computed tomography (CT) scan has ever been published. METHODS: Relevant CT scans were taken in the transverse, dorsal and longitudinal planes. These scans were compared with anatomical sections of heads. RESULTS: Computed tomography scans revealed almost all nasal structures, but cannot differentiate between the various layers of the nasal mucosa. Results show a double-scroll arrangement of the ventral nasal concha. The dorsal nasal concha protrudes into the maxillary sinus, but no protrusion into the frontal sinus was observed. The ethmoturbinate I is completely closed back on itself and rostrally voluminous. CONCLUSIONS: This work shows that at a clinical level, the integrity of the different turbinates can easily be appreciated from a simple CT scan. It will assist clinicians to evaluate pathological conditions that affect the nasal region.