A family of repetitive DNA sequences which comprise up to 15% of the genome of some waterfowl have previously been described. These sequences (RBMI sequences) were originally cloned from the redbreasted merganser: the species with the highest copy number. RBMI sequences are present in restriction enzyme digests as sets of fragments of discrete lengths indicating populations of various restriction morphs. Fragment sizes are conserved between related species and have been used to infer phylogenetic relationships. / In this study several major EcoRI restriction size classes of RBMI sequences were cloned and sequenced (2.6, 2.0, 1.7, and 0.6 kb fragments). The sequence elements present have several characteristics of retroposons; open reading frames, poly-A addition signals, and A-rich tails. The four clone types have overlapping regions of homology. In all 6 regions (A-F) are defined which are fragment size specific or are solely responsible for hybridization to a specific genomic restriction fragment. Probes for regions A-F were hybridized to Southern blots of DNA from related species. The organization of these sub-fragments is similar in the seven species tested. The genomic organization of these unique regions was investigated by Southern hybridization using probes for regions A-F against a time course of restriction enzyme digestion. Higher order structures were found in partial digests which indicate association of these sequences in larger discrete repeat units in the genome. Finally, partial MboI digest clones, containing RBMI sequences, were mapped with restriction enzymes, probes A-F, and total repetitive DNA. These studies indicate that regions A-F are present in the genome in several different organizations, some are flanked by unique DNA sequences, and that repetitive sequences other than regions A-F are present in these RBMI clusters. It is proposed that these sequences are of retropseudogene origin which were subsequently amplified as retroposons or as tandem repeats by recombination and/or slippage replication. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1305. / Director: Siwo R. deKloet. / Thesis (Ph.D.)--The Florida State University, 1994.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77166 |
| Contributors | McHugh, Kevin Patrick., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 131 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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