《科学》（20181207出版）一周论文导读(6)

在欧洲血统患者中的比例为3.6%，归因于新生显性突变的比例为50%。巴基斯坦血统患者中的比例更高，为31%。

[原文来自：www.11jj.com]

这种隐性负担的一半可归因于已知基因，研究者确定了两个与隐性发育障碍相关的基因，即KDM5B和EIF3F，并通过小鼠和细胞模型对其进行了功能验证。

研究结果表明隐性编码变异仅在目前未确诊的非血缘个体中占一小部分，对非编码变异、不完全外显率和多基因遗传疾病须进一步研究。

▲ Abstract

We estimated the genome-wide contribution of recessive coding variation in 6040 families from the Deciphering Developmental Disorders study. The proportion of cases attributable to recessive coding variants was 3.6% in patients of European ancestry, compared with 50% explained by de novo coding mutations. It was higher (31%) in patients with Pakistani ancestry, owing to elevated autozygosity. Half of this recessive burden is attributable to known genes. We identified two genes not previously associated with recessive developmental disorders, KDM5B and EIF3F, and functionally validated them with mouse and cellular models. Our results suggest that recessive coding variants account for a small fraction of currently undiagnosed nonconsanguineous individuals, and that the role of noncoding variants, incomplete penetrance, and polygenic mechanisms need further exploration.

考古与人类学 Archaeology& Anthropology

Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction

科学家揭示二叠纪末期海洋生物灭绝主要因素

▲ 作者：Justin L. Penn, Curtis Deutsch, Jonathan L. Payne, Erik A. Sperling

▲ 链接：

http://science.sciencemag.org/content/362/6419/eaat1327

▲ 摘要：

地球历史上最大规模的物种灭绝发生于二叠纪末期（约2.52亿年前），70%的陆地物种和96%的海洋生物从地球上消失，这一事件也被称为“大灭绝”。

该时期发生的气候骤变被认为是大灭绝的触发因素。

来自美国华盛顿大学和斯坦福大学的研究者提出了一种系统的地球模型，模拟了二叠纪与三叠纪之间的气候变化，重现了地质记录指明的海洋变暖和氧气流失情况，并使用代谢指数(Φ)评估这些变化对物种存活带来的影响。

模型显示的结果与古海洋学提供的灭绝记录相符，海洋变暖和氧气损失导致大量的海洋生物窒息而死，这应该是导致大灭绝的主要因素。

研究者还指出，这与现今地球变暖的情况有相似之处，值得人们警惕。

▲ Abstract

Rapid climate change at the end of the Permian Period (~252 million years ago) is the hypothesized trigger for the largest mass extinction in Earth’s history. We present model simulations of the Permian/Triassic climate transition that reproduce the ocean warming and oxygen (O2) loss indicated by the geologic record. The effect of these changes on animal survival is evaluated using the Metabolic Index (Φ), a measure of scope for aerobic activity governed by organismal traits sampled in diverse modern species. Modeled loss of aerobic habitat predicts lower extinction intensity in the tropics, a pattern confirmed with a spatially explicit analysis of the marine fossil record. The combined physiological stresses of ocean warming and O2 loss can account for more than half the magnitude of the “Great Dying.