Integrating cultural evolution and behavioral genetics

The 29 commentaries amplified our key arguments; offered extensions, implications, and applications of the framework; and pushed back and clarified. To help forge the path forward for cultural evolutionary behavioral genetics, we (1) focus on conceptual disagreements and misconceptions about the concepts of heritability and culture; (2) further discuss points raised about the intertwined relationship between culture and genes; and (3) address extensions to the proposed framework, particularly as it relates to cultural clusters, development, and power. These commentaries, and the deep engagement they represent, reinforce the importance of integrating cultural evolution and behavioral genetics

Cultural evolution of genetic heritability

Behavioral genetics and cultural evolution have both revolutionized our understanding of human behavior-largely independent of each other. Here we reconcile these two fields under a dual inheritance framework, offering a more nuanced understanding of the interaction between genes and culture. Going beyond typical analyses of gene-environment interactions, we describe the cultural dynamics that shape these interactions by shaping the environment and population structure. A cultural evolutionary approach can explain, for example, how factors such as rates of innovation and diffusion, density of cultural sub-groups, and tolerance for behavioral diversity impact heritability estimates, thus yielding predictions for different social contexts. Moreover, when cumulative culture functionally overlaps with genes, genetic effects become masked, unmasked, or even reversed, and the causal effects of an identified gene become confounded with features of the cultural environment. The manner of confounding is specific to a particular society at a particular time, but a WEIRD (Western, educated, industrialized, rich, democratic) sampling problem obscures this boundedness. Cultural evolutionary dynamics are typically missing from models of gene-to-phenotype causality, hindering generalizability of genetic effects across societies and across time. We lay out a reconciled framework and use it to predict the ways in which heritability should differ between societies, between socioeconomic levels and other groupings within some societies but not others, and over the life course. An integrated cultural evolutionary behavioral genetic approach cuts through the nature-nurture debate and helps resolve controversies in topics such as IQ

A decade after the metabolomics standards initiative it's time for a revision.

A recent analysis of publicly available metabolomics data shows that the MSI guidelines are not well abided to in publicly shared metabolomics studies. We propose that the MSI guidelines should be revisited and revised, as has been done in other communities, to fit the current community needs

Diversification and expression of the PIN, AUX/LAX, and ABCB families of putative auxin transporters in \u3cem\u3ePopulus\u3c/em\u3e

Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history, including both tandem and whole genome duplication as well as probable gene loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of genes involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ localization

Compliance with minimum information guidelines in public metabolomics repositories.

The Metabolomics Standards Initiative (MSI) guidelines were first published in 2007. These guidelines provided reporting standards for all stages of metabolomics analysis: experimental design, biological context, chemical analysis and data processing. Since 2012, a series of public metabolomics databases and repositories, which accept the deposition of metabolomic datasets, have arisen. In this study, the compliance of 399 public data sets, from four major metabolomics data repositories, to the biological context MSI reporting standards was evaluated. None of the reporting standards were complied with in every publicly available study, although adherence rates varied greatly, from 0 to 97%. The plant minimum reporting standards were the most complied with and the microbial and in vitro were the least. Our results indicate the need for reassessment and revision of the existing MSI reporting standards

Hydraulic properties of compression wood in branches and reoriented shoots of Douglas-fir (Psuedotsuga menziesii)

Xylem anatomy is a strong determinant of water transport efficiency and is therefore an important component of the overall hydraulic strategy of any woody plant. However, in addition to its role in water transport, xylem also serves in mechanical support, and these two functions may represent conflicting design requirements. To further our understanding of how mechanical requirements might affect water transport in woody plants, this research evaluates the efficiency with which compression wood, which is specialized to function in mechanical support, conducts water. Using young Douglas-fir (Pseudotsuga menziesii) trees, two modes of compression wood formation are considered: normally-growing branches and branches that take over as leaders. Lower branch halves, which contained large amounts of compression wood, were significantly limited in their ability to conduct water relative to upper halves. This is likely a result of their anatomy, as lower halves were denser and had shorter tracheids with narrower cell lumens than upper halves. Compression wood samples from branches that had taken over as leaders were also limited in their ability to conduct water, relative to samples from the wood formed opposite and to the sides of compression wood. In addition, compression wood samples from branches that had taken over as leaders were less permeable than lower branch halves. Despite the poor transport efficiency of lower branch halves, the amount of compression wood visible on the end of each branch segment did not explain any significant variation in whole segment hydraulic properties. This lack of relationship between compression wood and whole segment properties suggests that branches may make up for the lost conductive capacity in some way. In branches that replaced a missing leader, there was no evidence that xylem formed elsewhere in the segment (i.e., "opposite wood") made up for the loss through a concomitant increase in permeability. Instead, branches that replaced leaders increased their transport efficiency relative to normal branches through an increase in conducting cross-sectional area. Given the reduced permeability of compression wood, future work should address how woody plants minimize or counteract the detrimental effects of this mechanically-specialized xylem to fulfill their water transport needs

Compression wood has little impact on the water relations of Douglas-fir (Pseudotsuga menziesii) seedlings despite a large effect on shoot hydraulic properties

• Compression wood has been shown to reduce stem permeability, but it is not known to what extent it affects leaf‐level processes. Here, we report whole‐plant hydraulic properties of Douglas‐fir (Pseudotsuga menziesii) seedlings induced to form varying amounts of compression wood. • Seedlings were grown under three bending treatments to assess the impact of compression wood on hydraulic properties, including stomatal conductance (gs), above‐ground shoot conductance (Kl(abg)), and both specific and leaf area‐specific conductivity (ks and kl, respectively). • Kl(abg) was significantly lower (50% reduction) in severely bent seedlings than in controls. Similarly, both ks and kl of the main axis were significantly reduced (by 52% and 46%, respectively) in severely bent seedlings relative to controls. Seedlings in the moderate bending treatments had ks and kl that were intermediate between controls and severe bending. • Despite clear differences in above‐ground shoot hydraulic properties, severely bent seedlings maintained the same water potentials as controls and had similar diurnal patterns of gs. This suggests that when the entire soil–plant–atmosphere continuum is considered, even a severe reduction in stem ks caused by compression wood has little impact on leaf‐level processes.Keywords: biomechanic, stomatal conductance, reaction wood, tradeoff, hydraulic architecture, hydraulic conductivityKeywords: biomechanic, stomatal conductance, reaction wood, tradeoff, hydraulic architecture, hydraulic conductivit

Diversification and Expression of the PIN, AUX/LAX, and ABCB Families of Putative Auxin Transporters in Populus

Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history, including both tandem and whole genome duplication as well as probable gene loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of genes involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ localization

Differential regulation of auxin and cytokinin during the secondary vascular tissue regeneration in Populus trees

Tissue regeneration upon wounding in plants highlights the developmental plasticity of plants. Previous studies have described the morphological and molecular changes of secondary vascular tissue (SVT) regeneration after large-scale bark girdling in trees. However, how phytohormones regulate SVT regeneration is still unknown. Here, we established a novel in vitro SVT regeneration system in the hybrid aspen (Populus tremula x Populus tremuloides) clone T89 to bypass the limitation of using field-grown trees. The effects of phytohormones on SVT regeneration were investigated by applying exogenous hormones and utilizing various transgenic trees. Vascular tissue-specific markers and hormonal response factors were also examined during SVT regeneration. Using this in vitro regeneration system, we demonstrated that auxin and cytokinin differentially regulate phloem and cambium regeneration. Whereas auxin is sufficient to induce regeneration of phloem prior to continuous cambium restoration, cytokinin only promotes the formation of new phloem, not cambium. The positive role of cytokinin on phloem regeneration was further confirmed in cytokinin overexpression trees. Analysis of a DR5 reporter transgenic line further suggested that cytokinin blocks the re-establishment of auxin gradients, which is required for the cambium formation. Investigation on the auxin and cytokinin signalling genes indicated these two hormones interact to regulate SVT regeneration. Taken together, the in vitro SVT regeneration system allows us to make use of various molecular and genetic tools to investigate SVT regeneration. Our results confirmed that complementary auxin and cytokinin domains are required for phloem and cambium reconstruction.Peer reviewe