86.6 Mb
86.6%
Photos: Johanna Mappes and Ossi Nokelainen
The photo credits should be"Photo: Ossi Nokelainen (A-C), Samuel Waldron (D) and Bibiana Rojas (E)."
Here, we show that ignoring repeat-overlapping alignment seeds when aligning entire genomes misses numerous alignments between repetitive elements. We present a tool, RepeatFiller, that improves genome alignments by incorporating previously undetected local alignments between repetitive sequences. By applying RepeatFiller to genome alignments between human and 20 other representative mammals, we uncover between 22 and 84 Mb of previously undetected alignments that mostly overlap transposable elements. We further show that the increased alignment coverage improves the annotation of conserved non-exonic elements, both by discovering numerous novel transposon-derived elements that evolve under constraint and by removing thousands of elements that are not under constraint in placental mammals.
使用RepeatFiller重新分析人和其他20种有代表性的哺乳动物的基因组,发现了大量先前未检测到的序列比对,长度约在22 Mb到84 Mb之间,并且大多与转座元件位置重叠。研究进一步证明,序列比对覆盖度的提升可以发现许多新的进化保守的转座子衍生元件,并且排除了胎盘哺乳动物中非保守的数千个元件,从而提高保守非外显子元件的注释质量。
Trochodendron aralioides is the first chromosome-scale genome assembled in the order Trochodendrales. It represents the largest genome assembled to date in the basal eudicot grade, as well as the closest order relative to the core-eudicots, as the position of Buxales remains unresolved. This genome will support further studies of wood morphology and floral evolution, and will be an essential resource for understanding rapid changes that took place at the base of the Eudicot tree. Finally, it can further genome-assisted improvement for cultivation and conservation efforts of the wheel tree.
昆栏树是昆栏树目中第一个染色体水平组装的基因组。它代表了迄今为止在基部真双子叶类植物中组装的最大基因组,也是目前已发表基因组中与核心真双子叶最接近的。该基因组的发布将为进一步研究木材形态和花的进化提供支持,并将成为探究真双子叶植物早期快速分化的必要条件。最后,还进一步为基于基因组的昆栏树栽培和保育工作提供了可能。
该研究利用PacBio和Illumina NovaSeq测序,结合10X Genomics和Hi-C数据生成了679.56 GB的高质量读长。组装后昆栏树基因组大小约为1.614 Gb,scaffold N50为73.37 Mb。重复序列占基因组的64.226%,注释了35,328个蛋白质编码基因,每个基因平均有5.09个外显子。根据对蛋白质编码基因的系统发育分析和时间估算,发现昆栏树与黄杨目(研究中未取样)及核心真双子叶植物的最近共同祖先在121,8-125,8百万年前分开。
Papilio bianor Cramer, 1777 (commonly known as the Chinese peacock butterfly) (Insecta, Lepidoptera, Papilionidae) is a widely distributed swallowtail butterfly with a wide number of geographic populations ranging from the southeast of Russia to China, Japan, India, Vietnam, Myanmar, and Thailand. Its wing color consists of both pigmentary colored scales (black, reddish) and structural colored scales (iridescent blue or green dust). A high-quality reference genome of P. bianor is an important foundation for investigating iridescent color evolution, phylogeography, and the evolution of swallowtail butterflies.
近日,中国科学院昆明动物研究所李学燕副研究员带领的昆虫研究团队运用三代长读长测序技术,结合高通量染色体构象捕获(Hi-C)技术,成功地组装了碧凤蝶染色体水平的基因组,这是首个利用Hi-C技术完成的染色体水平的蝴蝶基因组。相关研究成果以Chromosomal-level reference genome of Chinese peacock butterfly (Papilio bianor)based 为题于2019年11月4日发表在Giga Science杂志。