|  See also
 UCLUST algorithm
 Abundance sort
 
Sort orderUCLUST assumes that input sequences are sorted in an order such that an 
appropriate centroid sequence is found before other members of its cluster. The two most common sort orders 
are 
summarized in the table below.
 
| Order | Description |  
| 
Decreasing length | 
This order is most appropriate when input sequences 
have large variations in length, e.g. because full-length sequences and 
fragments are both present, as shown in the figure below. However, with a length sort, the longest sequence may be an 
outlier. This can be addressed by recentering.
 |  
| 
Decreasing abundance | 
See abundance sorting.
 |  
  Multiple alignment of a cluster.
 The centroid (representative) sequence is shown in red.
 Fragments are poor centroids because member sequences may be
 dissimilar in the regions that do not align to the fragment (orange).
 
 |