Characterization of three chicken pseudogenes for U1 RNA.

Three chicken genomic DNA clones containing the U1 RNA sequence were isolated from a chicken gene library and characterized. Two of these clones, CL64 and CL111, are overlapping clones which show several single-nucleotide changes in the U1 coding sequence, suggesting that they probably are alleles of the same sequence. The U1 sequence in the third clone, CL40, is more divergent. Flanking regions of these genes do not share any sequence homology between each other or with the previously isolated chicken genomic clone CL59. A short repeat CGGGG appears 28 times upstream of the U1 sequence in CL59. Another repeat, GCACC, is repeated 14 times upstream of the U1 region in CL40.