Question about the depth of ONT ultra-long reads

[chenchen-eng]

I have noticed that the default parameter for '--ul-tip' is set to 6, which is explained as removing tip unitigs composed of less than or equal to INT reads during the ultra-long (UL) assembly process. Does this suggest that ONT ultra-long reads with a coverage depth of less than 6 are considered useless when using the default parameter? However, according to my testing, these ONT ultra-long reads still demonstrate an improvement in assembly continuity. Could this indicate that I have introduced an error somewhere? Thank you for your assistance.
（我注意到“--ul-tip”的默认参数是6，它的解释是remove tip unitigs composed of <=INT reads for the UL assembly。这是否意味了覆盖深度低于6的ONT ultra long reads使用默认参数是无用的。然而经过我的测试，这样的ONT ultra long reads仍然可以提升组装连续性，这是否说明了我引入了错误呢。谢谢！）

[chhylp123]

--ul-tip only works when there is a tip. It is fine that hifiasm may use very few UL reads to bridge gaps.