请问一下Minigraph-Cactus的脚本中提到了，所生成的三种文件，其中 clip graph: This is the default graph. Stretches of sequence >10kb that were not aligned to the underlying SV/minigraph are removed. "Dangling" nodes (ie that don't have an edge on each side) that aren't on the reference path are also removed, so that each chromosome only has two tips in the graph. 请问为什么要删除大于10KB的的序列，还有就是Dangling 是什么意思 前面的课程也没有说清楚，谢谢。