Behaviourally driven gene expression reveals song nuclei in hummingbird brain

Abstract

Two cautionary points, one perhaps encouraging and another less so, emerge from our study. First, it is evident that a high mutation rate is not always bene®cial. The adaptive neighbourhood of an adaptive peak can constrain evolvability, despite a high mutation rate. A high rate can lead to a high mutational load, as seen during the evolution by clone B. Thus, evolutionary changes in a population of RNA viruses, whether under clinical treatment or otherwise, should not automatically be interpreted as adaptive to the virus. Second, as had already been noted 12 , if multiple peaks exist, a shift to a new adaptive peak can be triggered by a costly resistance mutation and the ensuing compensatory mutations. If some peaks are higher, drugs should be used with caution not only because resistance can evolve but also because drug treatment can lead to the evolution of viruses that are more ®t rather than less. M Methods Strains and culture conditionsThe RNA bacteriophage f6 used in this study is a laboratory clone descended from the original isolate 15 . Populations A and B were generated in a previous study 7 . They are the end points of populations propagated using bottlenecks of 100 and 33 phage, respectively, to allow ®tness recovery after acquisition of a common deleterious mutation. Pseudomonas syringae sv. phaseolicola, the standard host of f6, was obtained from the American Type Culture Collection (ATCC# 21781), and Pseudomonas pseudocaligenes ERA, an alternate host, was obtained from L. Mindich. Details of diluting, ®ltering, culture and storage of phage and bacteria are published 16,17 . All phage and bacteria were grown in LC medium at 25 8C.

Rudimentary substrates for vocal learning in a suboscine

“…However, the RA cup in oscines and the Ai of pigeons do not project to vocal and respiratory nuclei of the midbrain, (DM) and medulla (RAm), nor does it play a role in vocalization 42 . The exact relation between forebrain control of vocalization and auditory relays has been described in much less detail in parrots 9,43 . Furthermore, the wing flapping behaviour associated with phoebe plastic song suggests a potential link between song production and a complementary motor behaviour in phoebes.…”

Social cues shift functional connectivity in the hypothalamus

“…We show here that both types of analyses contribute to understanding signal processing and highlight the potential for simultaneous consideration of multiple brain regions when estimating neural activity by using egr-1 expression, a marker previously used to map functional responses to sensory stimuli in individual brain nuclei (e.g., refs. [35][36][37][38]. Our analysis centered on the processing of acoustic communication signals in the túngara frog.…”

Quantification of developmental birdsong learning from the subsyllabic scale to cultural evolution

“…In contrast to auditory learning (the ability to discriminate between sounds), vocal learning (the ability to imitate complex sounds) is rare in nature, but in birds it probably evolved in three out of the 25-28 known orders: songbirds, parrots, and hummingbirds (13)(14)(15)(16)(17). Aside from humans, vocal learning in mammals has been conclusively demonstrated only in dolphins, whales (18), and bats (19), but not in apes.…”

“…2B) is connected to the vocal pathway and is directly involved in vocal learning ( Fig. 2B) (13)(14)(15)(16)(17). Given the sparseness of vocal learning across taxa, it is remarkable that the same specific gene, FOXP2, associated with vocal learning is found in both humans and songbirds.…”