Biology subjects

Ward, M. S.

Publications and source records attributed to Ward, M. S..

3 recordsLinked to original sources

bioRxiv2025

Tandem duplication of serpin genes yields functional variation and snake venom inhibitors.

Tandem duplication of genes can play a critical role in the evolution of functional novelty, but our understanding is limited concerning gene duplications role in coevolution between species. Much is known about the evolution and function of tandemly duplicated snake venom genes, however the potential of gene duplication to fuel venom resistance within prey species is poorly understood. In this study, we characterize patterns of gene duplication of the SERPINA subfamily of genes across in vertebrates and experimentally characterize functional variation in the SERPINA3-like paralogs of a wild rodent. We find the hallmarks of rapid birth-death evolution of SERPINA1-like and SERPINA3-like genes within and between rodent lineages. Next, we recombinantly expressed the 2 paralogous duplicates of SERPINA1 and 12 paralogous duplicates of SERPINA3 found in the genome of the big-eared woodrat (Neotoma macrotis), a species known to be resistant to protease-rich rattlesnake venoms. We found that two SERPINA3 paralogs inhibit snake venom serine proteases, indicating that these proteins have potential as resistance factors in SERPIN-mediated venom resistance. In addition, functional variation is apparent among paralogs, including neofunctionalization to inhibit both chymotrypsin-like and and trypsin-like proteases simultaneously for one venom-inhibiting paralog. Our results provide further evidence that the rapid evolution of SERPINA1 and SERPINA3 gene copy number across rodents has adaptive potential by producing functionally-diverse inhibitors.

evolutionary biology↗

bioRxiv2020

Change in terrestrial human footprint drives continued loss of intact ecosystems

Our ability to map humanitys influence across Earth has evolved, thanks to powerful computing, a network of earth observing satellites, and new bottom-up census and crowd-sourced data. Here, we provide the latest temporally inter-comparable maps of the terrestrial Human Footprint, and assessment of change in human pressure at global, biome, and ecoregional scales. In 2013, 42% of terrestrial Earth could be considered relatively free of anthropogenic disturbance, and 25% could be classed as wilderness (the least degraded end of the human footprint spectrum). Between 2000 and 2013, 1.9 million km2 - an area the size of Mexico - of land relatively free of human disturbance became highly modified. The majority of this occurred within tropical and subtropical grasslands, savannah, and shrubland ecosystems, but the rainforests of Southeast Asia also underwent rapid modification. Our results show that humanitys footprint is eroding Earths last intact ecosystems, and greater efforts are urgently needed to retain them.

ecology↗

bioRxiv2020

Only ten percent of the global terrestrial protected area network is connected via intact land

Land free of direct anthropogenic disturbance is considered essential for achieving biodiversity conservation outcomes but is rapidly eroding. In response, many nations are increasing their protected area estates but little consideration is given to the context of the surrounding landscape. This is despite the fact that connectivity between protected areas is critical in a changing climate and mandated in international protected area targets. By utilizing the latest human pressure assessment, which shows that [~]40% of the terrestrial planet is still intact, and a connectivity method, we found just 9.7% of Earths terrestrial protected network can be considered connected. On average, 11% of each nations protected area estate is connected via intact land. As the global community commits to bolder action on abating biodiversity loss, only an increased focus on landscape-scale habitat retention and restoration efforts will ensure those critical areas safeguarded for conservation outcomes will remain (or become) connected. One Sentence SummaryOnly 9.7% of the global protected area network can be considered connected by intact land.

ecology↗