Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals

Funding: Hoge Veluwe great tits: the NIOO-KNAW, ERC, and numerous funding agencies; Wytham great tits: Biotechnology and Biological Sciences Research Council, ERC, and the UK Natural Environment Research Council (NERC).The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.PostprintPeer reviewe

Genetic variance in fitness indicates rapid contemporary adaptive evolution in wild animals

The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change

Effects of social exclusion in trauma survivors with posttraumatic stress disorder

Trauma survivors with posttraumatic stress disorder (PTSD) often experience or report social stigmatization and isolation. Williams (2001) provided an experimental paradigm to assess behavioral effects of social exclusion. This paradigm (face-to-face version) has been applied in a 2 2 group experimental condition design. Participants in the PTSD group (N 16) and the nontraumatized control group (N 25) were randomly assigned to an exclusion or inclusion condition. The results showed interaction effects for main psychopathological assessments (depression, anxiety, psychoticism) and expected main effects for the majority of outcome measures (psychopathology, well-being, belonging, and meaningful existence). The research concludes that a general assumption of elevated levels of self-perceived social exclusion in PTSD patients has to be considered in terms of differentiated psychopathological effects of exclusion

Social Cognition and Interpersonal Impairments in Trauma Survivors with PTSD

Trauma survivors with posttraumatic stress disorder (PTSD) often experience psychosocial problems. This article reviews interpersonal factors such as social support, social acknowledgment, and interpersonal impairment that are relevant to the development and maintenance of PTSD. Furthermore, it considers the possible impact of social cognition on PTSD. The capacity to empathize (empathy) and the existence of an individual “theory of mind” are fundamental to human social interaction. We raise the question of whether traumatic experiences may lead to changes in the social cognition of traumatized individuals. The possible effects of perceived social exclusion as a maintenance factor for PTSD are also discussed

Are empathic abilities impaired in posttraumatic stress disorder?

Trauma survivors with PTSD show social interaction and relationship impairments. It is hypothesized that traumatic experiences lead to known PTSD symptoms, empathic ability impairment, and difficulties in sharing affective, emotional, or cognitive states. A PTSD group (N=16) and a nontraumatized Control group (N=16) were compared on empathic abilities, namely the Empathic Resonance Test, Reading the Mind in the Eyes Test, and Faux Pas Test. The Interpersonal Reactivity Index as a self-report measure of empathy and measures of non-social cognitive functions, namely the Verbal Fluency Test, the Five-Point Test, and the Stroop Test, were also administered. The PTSD group showed lower empathic resonance. No clear indications of other impairments in social cognitive functions were found. The PTSD group had significantly higher personal distress. Empathic resonance impairments did not correlate with subjective severity of PTSD symptomatology. This article discusses whether impaired empathic resonance in PTSD trauma survivors is a consequence of trauma itself or a protective coping strategy

Hybrid ancestry of an island subspecies of Galápagos mockingbird explains discordant gene trees

Introgression of genes through hybridization has been proposed to be an important driver of speciation, but in animals this has been shown only in relatively few cases until recently. Additionally, introgressive hybridization among non-sister species leads to a change in the gene tree topology of the concerned loci and thus complicates phylogenetic reconstruction. However, such cases of ancient introgression have been very difficult to demonstrate in birds. Here, we present such an example in an island bird subspecies, the Genovesa mockingbird (Mimus parvulus bauri). We assessed phylogenetic relationships and population structure among mockingbirds of the Galápagos archipelago using mitochondrial and nuclear DNA sequences, autosomal microsatellites, and morphological measurements. Mitochondrial haplotypes of Genovesa mockingbirds clustered closely with the haplotypes from two different species, San Cristóbal (M. melanotis) and Española (M. macdonaldi) mockingbirds. The same pattern was found for some haplotypes of two nuclear gene introns, while the majority of nuclear haplotypes of Genovesa mockingbirds were shared with other populations of the same species (M. parvulus). At 26 autosomal microsatellites, Genovesa mockingbirds grouped with otherM. parvuluspopulations. This pattern shows that Genovesa mockingbirds contain mitochondria and some autosomal alleles that have most likely introgressed from M. melanotisinto a largely M. parvulusbackground, making Genovesa mockingbirds a lineage of mixed ancestry, possibly undergoing speciation. Consistent with this hypothesis, mockingbirds on Genovesa are more clearly differentiated morphologically from otherM. parvuluspopulations thanM. melanotis is from M. parvulus

Mirror neuron activity during contagious yawning—an fMRI study

Yawning is contagious. However, little research has been done to elucidate the neuronal representation of this phenomenon. Our study objective was to test the hypothesis that the human mirror neuron system (MNS) is activated by visually perceived yawning. We used functional magnetic resonance imaging to assess brain activity during contagious yawning (CY). Signal-dependent changes in blood oxygen levels were compared when subjects viewed videotapes of yawning faces as opposed to faces with a neutral expression. In response to yawning, subjects showed unilateral activation of their Brodmann's area 9 (BA 9) portion of the right inferior frontal gyrus, a region of the MNS. In this way, two individuals could share physiological and associated emotional states based on perceived motor patterns. This is one component of empathy (motor empathy) that underlies the development of cognitive empathy. The BA 9 is reportedly active in tasks requiring mentalizing abilities. Our results emphasize the connection between the MNS and higher cognitive empathic functions, including mentalizing. We conclude that CY is based on a functional substrate of empathy