bioRxiv Science⌕ Search

Biology subjects

Xu, A. L.

Publications and source records attributed to Xu, A. L..

2 recordsLinked to original sources

A comprehensive analysis of grazing: Improving management for environmental health

In an effort to combat the dual climate and biodiversity crises, the international community has put forth targets to reduce emissions and protect species. Habitat degradation is at the fore in driving species extinctions and carbon loss, creating an urgent need to examine our land-use practices if we are to meet international goals. Individual nations will have differing needs and approaches to reaching these objectives based on their landscapes, industries, and levels of historic overuse. In the United States, grazing is the leading land-use, making up approximately one-third of the country. Here we present a broad-scale analysis of how grazing effects the environment and examine how this land-use plays out across the U.S. This review can help policy makers and land managers strategically assess grazing lands as we work towards a national landscape that supports equitable ecosystem services, sustainable livelihoods, and climate resilience. HighlightsO_LILivestock grazing can have a multitude of effects on local ecosystems often causing habitat degradation and loss. As this land-use makes up a third of U.S. lands, improving grazing practices could provide significant benefits for the environment. C_LIO_LITo our knowledge, this is the largest review of U.S. grazing to date. We explore how grazing affects six elements of the environment across the country. C_LIO_LIWhile the majority of literature discusses negative implications related to grazing, our results indicate that regions are affected differently, and that management and livestock-type also contribute to the overall environmental impact. C_LI

ecology↗

The RAG transposon is active through the deuterostome evolution and domesticated in jawed vertebrates.

RAG1 and RAG2 are essential subunits of the V(D)J recombinase required for the generation of the variability of antibodies and T-cell receptors in jawed vertebrates. It was demonstrated that the amphioxus homologue of RAG1-RAG2 is encoded in an active transposon, belonging to the transposase DDE superfamily. The data provided supports to the possibility that the RAG transposon has been active through the deuterostome evolution and is still active in several lineages. The RAG transposon corresponds to several families present in deuterostomes. RAG1-RAG2 V(D)J recombinase evolved from one of them, partially due to the new ability of the transposon to interact with the cellular reparation machinery. Considering the fact that the RAG transposon survived millions of years in many different lineages, in multiple copies, and that DDE transposases evolved their association with proteins involved in repair mechanisms, we propose that the apparition of V(D)J recombination machinery could be a predictable genetic event.

immunology↗