Extreme variability among mammalian V1R gene families

Abstract

We report an evolutionary analysis of the V1R gene family across 37 mammalian genomes. V1Rs comprise one of three chemosensory receptor families expressed in the vomeronasal organ, and contribute to pheromone detection. We first demonstrate that Trace Archive data can be used effectively to determine V1R family sizes and to obtain sequences of most V1R family members. Analyses of V1R sequences from trace data and genome assemblies show that species-specific expansions previously observed in only eight species were prevalent throughout mammalian evolution, resulting in ''semiprivate'' V1R repertoires for most mammals. The largest families are found in mouse and platypus, whose V1R repertoires have been published previously, followed by mouse lemur and rabbit (~215 and~160 intact V1Rs, respectively). In contrast, two bat species and dolphin possess no functional V1Rs, only pseudogenes, and suffered inactivating mutations in the vomeronasal signal transduction gene Trpc2. We show that primate V1R decline happened prior to acquisition of trichromatic vision, earlier during evolution than was previously thought. We also show that it is extremely unlikely that decline of the dog V1R repertoire occurred in response to selective pressures imposed by humans during domestication.

De novo microduplication of the FMR1 gene in a patient with developmental delay, epilepsy and hyperactivity

“…25 A third gene in our patient's 1q44 gain, VN1R5, is thought to be a pseudogene. 26 None of these genes have been reported as causative of human disease. The 4p15 loss has been reported as a normal copy number variant in the Database of Genomic Variants (http://projects.tcag.ca/variation).…”

Strong links between genomic and anatomical diversity in both mammalian olfactory chemosensory systems

“…We compiled data on the olfactory genomes by recoding published values reported in Hayden et al [4] and Matsui et al [35] for the OR gene family, and Young et al [18] for the V1R gene family. From these data, we calculated the total number of genes, the total number of presumed functional/intact genes and the proportion of functional/intact genes for both gene families (electronic supplementary material, table S1).…”

Early development of the nervous system of the eutherian <i>Tupaia belangeri</i>

“…Testing panels of calcium-binding proteins also facilitates functional studies of calcium-controlled processes, for example, in the frameworks of pulse stimulation of isolated olfactory neurons with odors and isobutylmethylxanthine/forskolin (Zhang and Delay, 2006) or following urine stimulation of the mouse vomeronasal organ, which activates largeconductance Ca 2+ -activated K + channels (Zhang et al, 2008). Finally, a good understanding of the expression patterns of calcium-binding proteins helps to find answers to evolutionary biological problems, e.g., when analyzing the vomeronasal type 1 receptor (V1R) family (Young et al, 2010). One of the interesting results of this study is that "almost all of the species with large V1R repertoires have welldeveloped vomeronasal organs and/or AOBs [accessory olfactory bulbs]".…”