首先在UCSC的https://genome.ucsc.edu/cgi-bin/hgTables 里面下载下面这个文件：
image.png
可以看到我这里选择的mm10的refseq系统的所有基因，共有29037个不同的tss，36872个转录本，只有24540个基因，说明有部分基因有多个tss，这个其实挺麻烦的。
#bin name chrom strand txStart txEnd cdsStart cdsEnd exonCount exonStarts exonEnds score name2 cdsStartStat cdsEndStat exonFrames0 NM_001282945 chr1 - 134199214 134235457 134202950 134234355 3 134199214,134234014,134235227, 134203590,134234446,134235457, 0 Adora1 cmpl cmpl 2,0,-1,0 NM_001039510 chr1 - 134199214 134235457 134202950 134234355 3 134199214,134234014,134235227, 134203590,134234412,134235457, 0 Adora1 cmpl cmpl 2,0,-1,0 NM_001291930 chr1 - 134199214 134235457 134202950 134203505 2 134199214,134235227, 134203590,134235457, 0 Adora1 cmpl cmpl 0,-1,0 NM_001291928 chr1 - 134199214 134234856 134202950 134234733 2 134199214,134234662, 134203590,134234856, 0 Adora1 cmpl cmpl 2,0,0 NM_001008533 chr1 - 134199214 134235457 134202950 134234355 2 134199214,134234014, 134203590,134235457, 0 Adora1 cmpl cmpl 2,0,
其实里面可以设置直接下载所有基因的TSS区域的bed文件，可是我不会设置各种参数，也懒得去摸索，直接对上面的文件我可以写脚本处理得到需要的数据形式。 需要输出的是bed格式文件，如下： chrom / chromStart /chromEnd /name /score /strand 我这里定义的TSS(转录起始位点)区域上下游2.5kb，所以代码如下：
<pre class="prism-token token language-javascript" style="box-sizing: border-box; list-style: inherit; margin: 0.5em 0px; padding: 1em; color: rgb(204, 204, 204); background: rgb(80, 85, 107); border-radius: 3px; overflow: auto; font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace; overflow-wrap: normal; text-align: left; white-space: pre; word-spacing: 0px; word-break: normal; line-height: 1.5; tab-size: 4; hyphens: none; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">perl -alne '{next if /^#/;if($F[3] eq "+"){$start=$F[4]-2500;$end=$F[4]+2500}else{$start=$F[5]-2500;$end=$F[5]+2500}print join("\t",$F[2],$start,$end,$F[12],0,$F[3])}' ucsc.refseq.txt |sort -u >ucsc.refseq.tss.bed</pre>
最后得到的文件如下：
<pre class="prism-token token language-javascript" style="box-sizing: border-box; list-style: inherit; margin: 0.5em 0px; padding: 1em; color: rgb(204, 204, 204); background: rgb(80, 85, 107); border-radius: 3px; overflow: auto; font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace; overflow-wrap: normal; text-align: left; white-space: pre; word-spacing: 0px; word-break: normal; line-height: 1.5; tab-size: 4; hyphens: none; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">tail ucsc.refseq.tss.bed chrY 816212 821212 Uba1y 0 +chrY 81798997 81803997 Gm20747 0 -chrY 82222714 82227714 Gm20736 0 +chrY 83925411 83930411 Gm20854 0 -chrY 85527019 85532019 Gm20854 0 -chrY 8832669 8837669 Gm20815 0 -chrY 895287 900287 Kdm5d 0 +chrY 90752550 90757550 G530011O06Rik 0 -chrY 90782941 90787941 Erdr1 0 +chrY 90836906 90841906 G530011O06Rik 0 </pre>
这里面会有一个问题，对于部分基因在非正常染色体的，会出现如下诡异的结果，建议干脆删除掉。
<pre class="prism-token token language-javascript" style="box-sizing: border-box; list-style: inherit; margin: 0.5em 0px; padding: 1em; color: rgb(204, 204, 204); background: rgb(80, 85, 107); border-radius: 3px; overflow: auto; font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace; overflow-wrap: normal; text-align: left; white-space: pre; word-spacing: 0px; word-break: normal; line-height: 1.5; tab-size: 4; hyphens: none; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">chr4_GL456216_random 13380 18380 Dhrsx 0 +chr4_GL456350_random -1369 3631 Ccl21c 0 -chr4_GL456350_random -1369 3631 Gm10591 0 -chr4_GL456350_random -1369 3631 Gm13304 0 -</pre>
记住，这个时候，部分基因还有多个tss哦，反正取决于你的下游分析流程啦。
