There are two ways of finding the root of a phylogenetic tree. The first is to include one or more sequences in the data set that are known to lie outside the diversity of the sequences of interest. These sequences are usually referred to as the 'outgroup'.For example, in the trees above, the pair of tips labelled 'virus9' and 'virus10' could be the outgroup allowing us to root the tree at the red circle.hese sequences are usually referred to as the 'outgroup'. For example, in the trees above, the pair of tips labelled 'virus9' and 'virus10' could be the outgroup allowing us to root the tree at the red circle.
The origin of the prefix anti- and its variant ant- is an ancient Greek word which meant âagainstâ or âopposite.â These prefixes appear in numerous English vocabulary words, such as antifreeze, antidote, antonym, and antacid.
Answer   The prefix a means not or against.   No the prefix a does not meant against....the prefix for against or opposing to is contra   The prefix a just me â¦ ans, without, lacking or not.