Category Archives: Computational Genomics

我在中科院昆明植物开始新的研究

在经历了短暂的公司研发后, 从2018年7月起, 我又回到学术圈在中国科学院昆明植物所做PI,领导一个生物信息学研究的实验室,从事二代、三代基因组数据的从头组装、遗传变异分析和相关的比较基因组学研究。 研究方向主要侧重于应用统计/概率论理论,机器学习(统计学习)算法到最新的计算生物学问题中,特别关注的数据是植物基因组。

欢迎有兴趣的同仁加盟我们实验室。实验室现有助理研究员、博士后、研究生和客座研究生等职位开放,欢迎有计算机、数学、物理或具有生物信息应用技术背景的人应聘。

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Sclust paper published on NP

After years fighting, our Sclsut paper published on Nature Protocols finally. Enjoy!

Yupeng Cun, Tsun-Po Yang, Viktor Achter*, Ulrich Lang, Martin Peifer, Copy number analysis and inference of subclonal populations in cancer genomes using Sclust. Nature Protocols, 2018,DOI: 10.1038/nprot.2018.033
Sclust download link: rj.run/downloads/Sclust.tgz)


Frequent Q&A on Sclust software package uses:

A new fast method for copy number calling, tissue purity estimating and subclone inferring in cancer genome

Our new methods final launched on Nature Protocols, where we developed a series of methods and related C++/R combined software package,  Sclust(around 1.5Gb,大文件谨慎载). In Sclust, you can do copy number calling, cancer tissue purity estimating and clone and subclone structure inferring from normal-tumor paired whole genome/exon sequencing data.

先总结一下,我们方法的有如下点:

1. 可以准确地做copy number calling, tumor purity estimating,subclonal inferring;

2. subclonal inferring的速度超级快。4000~6000 个SNVs 的 clonal inferring 过程在个人电脑上只需3到5秒。

3. sclust 给出了每个集群的倍数树变异,目前只有少数个软件提供这个功能。

欢迎使用软件,欢迎咨询,欢迎交流。

联系邮件:yp.cun@outlook.com。 下面是clonal 推断一些背景。

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Inferring tumour evolution 2 – Comparison to classical phylogenetics

Scientific B-sides

Quick recap: Last time we talked about tumor evolution and I presented a toy example to introduce key concepts. I also introduced the intra-tumor phylogeny problem: Given a sample of the genomes of clones in a tumour, reconstruct its `life history’. This problem consists of two sub-problems: (1)identification of clones, and (2) inferring evolutionary relationships between clones.

This problem falls into the general area of reconstructing phylogenetic trees — so how does inferring clonal trees compare to classical phylogenetic methods?

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Inferring tumour evolution 1 – The intra-tumour phylogeny problem

Scientific B-sides

“Cancer evolves dynamically as clonal expansions supersede one another driven by shifting selective pressures, mutational processes, and disrupted cancer genes. These processes mark the genome, such that a cancer’s life history is encrypted in the somatic mutations present,”

write Nik-Zainal et al in the abstract of their 2012 Cell paper `The life history of 21 breast cancers‘. The key figure of their paper shows a phylogenetic tree of tumor development in a patient. The paper contains lots of computational work on analyzing and interpreting mutations based on deep-sequencing data, but –a big surprised but— the very last step of putting together the tree was done manually. Half the paper is describing the reasoning that Peter Campbell and his group used to condense all the evidence they had gathered from genomic data into the tree – but there is no algorithm.

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