Identification of novel CR1 subfamilies in an avian order with recently active elements.

Chicken repeat 1 (CR1) is a taxonomically widespread non-LTR retrotransposon. Recent CR1 retrotranspositions in waterfowl suggested that, unlike chicken at least one subfamily remains active. Based on sequence information from 143 CR1 loci, six distinct groups of CR1 within the waterfowl coscoroba each with unique 3' untranslated regions and distinct open reading frames are described. Through comparison to other previously described avian CR1 subfamilies, it is shown that five of the six coscoroba groups represent new subfamilies. At least one of these subfamilies is likely active and provides a target for future isolation of the first active member of this taxonomically widespread non-LTR family.