Cattle genome-wide analysis reveals genetic signatures in trypanotolerant N'Dama

Abstract Background Indigenous cattle in Africa have adapted to various local environments to acquire superior phenotypes that enhance their survival under harsh conditions. While many studies investigated the adaptation of overall African cattle, genetic characteristics of each breed have been poorly studied. Results We performed the comparative genome-wide analysis to assess evidence for subspeciation within species at the genetic level in trypanotolerant N’Dama cattle. We analysed genetic variation patterns in N’Dama from the genomes of 101 cattle breeds including 48 samples of five indigenous African cattle breeds and 53 samples of various commercial breeds. Analysis of SNP variances between cattle breeds using wMI, XP-CLR, and XP-EHH detected genes containing N’Dama-specific genetic variants and their potential associations. Functional annotation analysis revealed that these genes are associated with ossification, neurological and immune system. Particularly, the genes involved in bone formation indicate that local adaptation of N’Dama may engage in skeletal growth as well as immune systems. Conclusions Our results imply that N’Dama might have acquired distinct genotypes associated with growth and regulation of regional diseases including trypanosomiasis. Moreover, this study offers significant insights into identifying genetic signatures for natural and artificial selection of diverse African cattle breeds

Attraction and localization of round goby (Neogobius melanostomus) to conspecific calls

Many species of fish use auditory cues as part of their reproductive repertoire but intended receivers must be able to localize sounds to make full use of this information. Specialized couplings between the ear and swim bladder are thought to be critical for acoustic localization, yet species without specialized connections use acoustic cues in reproductive displays. In an attempt to better understand mechanisms of acoustic localization, we used the round goby (Neogobius melanostomus), a hearing generalist, to assess responses to calls in the lab and field. The call used for playback was recorded in the field from an actively displaying male round goby and consisted of a series of low frequency pulses. In the field, playback of the call resulted in a significant enhancement of approaches toward, and entries into, an experimental arena as compared to when the sound was off. There was no effect on the amount of time spent near the speaker however. In the lab, males and females responded actively when calls were played and females showed a significant attraction to the playing speaker. Responses were highly directional with little angular deviation, suggesting true localization to the sound source. While the sensory mechanisms allowing round gobies to selectively respond to conspecific vocalizations remain unknown, it is clear that they do show highly directional responses to acoustic cues in both laboratory and field settings

In situ investigation of burst swimming and muscle performance in the deep-sea fish Antimora rostrata (Gunther, 1878)

The few existing measurements of deep-sea fish physiology consistently indicate reduced basal metabolism and metabolic power. A possible explanation for this is the reduction in selective pressure for burst activity capacity due to a reduction in the frequency and duration of predator-prey interactions in the sparsely distributed fish community and continuous darkness. Video recordings of stimulated fast-starts in deep-sea fish were obtained by a lander vehicle and analysed to give the swimming velocities, accelerations, and inertial power requirements of fast-start swimming in Antimora rostrata. With a mean peak velocity of 0.7 m s(-1), and white muscle power output of only 17.0 W kg(-1). A. rostrata is a slow moving fish, but no slower than shallow-water fishes at the same temperature