Evolution of a novel adrenal cell type that promotes parental care.

Cell types with specialized functions fundamentally regulate animal behaviour, and yet the genetic mechanisms that underlie the emergence of novel cell types and their consequences for behaviour are not well understood. Here we show that the monogamous oldfield mouse (Peromyscus polionotus) has recently evolved a novel cell type in the adrenal gland that expresses the enzyme AKR1C18, which converts progesterone into 20α-hydroxyprogesterone. We then demonstrate that 20α-hydroxyprogesterone is more abundant in oldfield mice, where it induces monogamous-typical parental behaviours, than in the closely related promiscuous deer mice (Peromyscus maniculatus).

Post-mating parental behavior trajectories differ across four species of deer mice.

Among species, parental behaviors vary in their magnitude, onset relative to reproduction, and sexual dimorphism. In deer mice (genus Peromyscus), while most species are promiscuous with low paternal care, monogamy and biparental care have evolved at least twice under different ecological conditions. Here, in a common laboratory setting, we monitored parental behaviors of males and females of two promiscuous (eastern deer mouse P.

Allele-specific cis-regulatory methylation of the gene for vasoactive intestinal peptide in white-throated sparrows.

White-throated sparrows (Zonotrichia albicollis) offer a unique opportunity to connect genotype with behavioral phenotype. In this species, a rearrangement of the second chromosome is linked with territorial aggression; birds with a copy of this "supergene" rearrangement are more aggressive than those without it. The supergene has captured the gene VIP, which encodes vasoactive intestinal peptide, a neuromodulator that drives aggression in other songbirds.

Inside the supergene of the bird with four sexes.

The white-throated sparrow (Zonotrichia albicollis) offers unique opportunities to understand the adaptive value of supergenes, particularly their role in alternative phenotypes. In this species, alternative plumage morphs segregate with a nonrecombining segment of chromosome 2, which has been called a 'supergene'. The species mates disassortatively with respect to the supergene; that is, each breeding pair consists of one individual with it and one without it.

A supergene-linked estrogen receptor drives alternative phenotypes in a polymorphic songbird.

Behavioral evolution relies on genetic changes, yet few behaviors can be traced to specific genetic sequences in vertebrates. Here we provide experimental evidence showing that differentiation of a single gene has contributed to the evolution of divergent behavioral phenotypes in the white-throated sparrow, a common backyard songbird. In this species, a series of chromosomal inversions has formed a supergene that segregates with an aggressive phenotype.

Rapid effects of 17β-estradiol on aggressive behavior in songbirds: Environmental and genetic influences.

Contribution to Special Issue on Fast effects of steroids. 17β-estradiol (E) has numerous rapid effects on the brain and behavior. This review focuses on the rapid effects of E on aggression, an important social behavior, in songbirds.

Rapid effects of estradiol on aggression depend on genotype in a species with an estrogen receptor polymorphism.

The white-throated sparrow (Zonotrichia albicollis) represents a powerful model in behavioral neuroendocrinology because it occurs in two plumage morphs that differ with respect to steroid-dependent social behaviors. Birds of the white-striped (WS) morph engage in more territorial aggression than do birds of the tan-striped (TS) morph, and the TS birds engage in more parenting behavior. This behavioral polymorphism is caused by a chromosomal inversion that has captured many genes, including estrogen receptor alpha (ERα).

The impact of mechanically stimulated muscle-derived stromal cells on aged skeletal muscle.

Perivascular stromal cells, including mesenchymal stem/stromal cells (MSCs), secrete paracrine factor in response to exercise training that can facilitate improvements in muscle remodeling. This study was designed to test the capacity for muscle-resident MSCs (mMSCs) isolated from young mice to release regenerative proteins in response to mechanical strain in vitro, and subsequently determine the extent to which strain-stimulated mMSCs can enhance skeletal muscle and cognitive performance in a mouse model of uncomplicated aging. Protein arrays confirmed a robust increase in protein release at 24h following an acute bout of mechanical strain in vitro (10%, 1Hz, 5h) compared to non-strain controls.

Mouse genetic differences in voluntary wheel running, adult hippocampal neurogenesis and learning on the multi-strain-adapted plus water maze.

Moderate levels of aerobic exercise broadly enhance cognition throughout the lifespan. One hypothesized contributing mechanism is increased adult hippocampal neurogenesis. Recently, we measured the effects of voluntary wheel running on adult hippocampal neurogenesis in 12 different mouse strains, and found increased neurogenesis in all strains, ranging from 2- to 5-fold depending on the strain.