24小时热门版块排行榜

返回列表

当前主题已经存档。

leiqian

银虫 (小有名气)

应助: 0 (幼儿园)
金币: 661.5
帖子: 80
在线: 5.3小时
虫号: 575010
注册: 2008-06-17
性别: MM
专业: 色谱分析

[交流] 【求助】请教用MEGA4做进化树的问题

不知道有没有用过MEGA4做进化树的虫子。想请教个问题
MEGA4做进化树对序列的多少有没有限制呀，我把我的409条蛋白质序列全部选中，然后用NJ建树，结果显示“No commom sites found for computing distances".而我随便选取其中一些序列作树时，就可以成功。这是为什么呢？我现在是需要对所有序列建树呀，该怎么办？
不知道有没有人知道，帮忙解答一下，不胜感激！
http://www.megasoftware.net

回复此楼

» 猜你喜欢

1楼 2009-03-03 15:30:00

已阅回复此楼关注TA 给TA发消息送TA红花 TA的回帖

holy518125

金虫 (小有名气)

应助: 4 (幼儿园)
金币: 618
散金: 66
帖子: 85
在线: 54.5小时
虫号: 475459
注册: 2007-12-07
性别: GG
专业: 昆虫学

You must identify which taxon has no common sites with others, and then remove them in order to continue your computing. Please follow this procedure to check the number of common sites between taxa:

1. Click Distances|Compute pairwise from the main menu
2. In the Analysis Preference window, select " L: No. of Valid Common Sites" from drop down for the option "Substitutions to Include"
3. Click "compute" button to get a matrix.

The number in the matrix indicates the number of common sites between sequences that are available for analysis. When this number is zero, there are no common sites. To get around this problem, you may want to eliminate some sequences. In addition, the use of the "Pairwise-Deletion" option for handling alignment gaps and missing data may also be employed.