sjj at sanger.ac.uk
Wed Aug 7 08:36:31 EST 1996
There are two basic types of repeats that are found in the
Firstly there are the local repetitive regions. This category
includes tandemly repeated sequences and inverted repeats. In C. elegans
about 4% of the current genomic sequence is occupied by the arms of inverted
repeats whilst around 9% is between such arms. A further 2.2% of the current
genomic sequence is made up of tandem repeats. These figures are depend strongly
however on the stringency of the search criteria e.g. how identical do the
arms of an inverted repeat have to be and how far apart can they be.
In the same way, how divergeant can the individual units of a tandem repeat
be and still be determined as part of a tandem array. The above figures are
calculated using relatively stringent criteria.
Secondly, there are the repeat families or long range repeats i.e.
similar sequences found numerous times throughout the genome. Currently
we have defined 17 of these families which in total occupy about 1.7% of the current
genomic sequence. Many more such families are currently being characterised.
The Sanger Centre
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