The time is ripe for functional genomics: Can epigenetic changes mediate reproductive timing?

Populations are under strong selection to match reproductive timing with favourable environmental conditions. This becomes particularly important and challenging with increasing interannual environmental variability. Adjusting reproductive timing requires the ability to sense and interpret relevant environmental cues, while responding flexibly to their interannual variation. For instance, in seasonal species, reproductive timing is often dependent on photoperiod and temperature. Although many genes influencing the timing of reproduction have been identified, far less attention has been paid to the gene-regulatory cascades orchestrating these complex gene-environment interactions. In a From the Cover article in this issue of Molecular Ecology, Lindner, Laine, et al. (2021) addressed this knowledge gap by investigating the role of DNA methylation in mediating reproductive timing in the seasonally breeding great tit (Parus major). Using a clever blood sampling design, they investigated genome-wide DNA methylation changes following individual female birds across multiple reproductive stages. This approach revealed 10 candidate genes with a strong correlation between promoter methylation and reproductive status. Some of these genes are known to be involved in reproductive timing (e.g., MYLK-like or NR5A1), yet for others this function was previously unknown (Figure 1). Interestingly, NR5A1 is a key transcription factor, which may affect other genes that are part of the same regulatory network. The findings of Lindner, Laine, et al. (2021) provide a strong case for studying DNA methylation to uncover how gene-environment interactions influence important life-history traits, such as reproductive timing

Genome-wide association analysis of stalk biomass and anatomical traits in maize.

BackgroundMaize stover is an important source of crop residues and a promising sustainable energy source in the United States. Stalk is the main component of stover, representing about half of stover dry weight. Characterization of genetic determinants of stalk traits provide a foundation to optimize maize stover as a biofuel feedstock. We investigated maize natural genetic variation in genome-wide association studies (GWAS) to detect candidate genes associated with traits related to stalk biomass (stalk diameter and plant height) and stalk anatomy (rind thickness, vascular bundle density and area).ResultsUsing a panel of 942 diverse inbred lines, 899,784 RNA-Seq derived single nucleotide polymorphism (SNP) markers were identified. Stalk traits were measured on 800 members of the panel in replicated field trials across years. GWAS revealed 16 candidate genes associated with four stalk traits. Most of the detected candidate genes were involved in fundamental cellular functions, such as regulation of gene expression and cell cycle progression. Two of the regulatory genes (Zmm22 and an ortholog of Fpa) that were associated with plant height were previously shown to be involved in regulating the vegetative to floral transition. The association of Zmm22 with plant height was confirmed using a transgenic approach. Transgenic lines with increased expression of Zmm22 showed a significant decrease in plant height as well as tassel branch number, indicating a pleiotropic effect of Zmm22.ConclusionSubstantial heritable variation was observed in the association panel for stalk traits, indicating a large potential for improving useful stalk traits in breeding programs. Genome-wide association analyses detected several candidate genes associated with multiple traits, suggesting common regulatory elements underlie various stalk traits. Results of this study provide insights into the genetic control of maize stalk anatomy and biomass

Requirements of 4G-Based Mobile Broadband on Future Transport Networks

Long term evolution technologies provide new standards in mobile communications regarding available bandwidth. It is expected that users of one radio cell will share more than 100 Mbit/s in future. To take advantage of the full feature set of next generation mobile networks, transport network design has to face new requirements, caused by the architectural changes of LTE technologies. Especially the newly defined X2 interface impacts on the transport network requirements. X2 enables direct communication between evolved base stations (eNBs) and thus, enforces local solutions. At the same time a tendency of locating network elements at fewer, central sites to reduce operational expenditure can be observed, in particular concerning the transport layer. This leads to the question of how the direct X2 connection of eNBs on the logical layer can be accommodated with a general centralization of transport networks. Our considerations show that for LTE, a centralized transport network is able to realize the local meshing between eNBs. However, for LTE Advanced, the standards currently discussed by the 3GPP initiative could lead to enhanced requirements on the X2 interface latency. Consequently, the implications for the network architecture have to be analyzed in more detail