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Title: Studies on the molecular biology of sex determination in the tilapias
Author: McConnell, S. K. J.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1993
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This study set out to develop molecular biological techniques for the study of sex determination in the tilapias, and, in particular, in Oreochromis niloticus (Linnaeus), Lake Manazala strain. Two heterospecific probes, pDP1007 (supplied by Dr. D. Page) which gives a Y-chromosome specific hybridization pattern in humans, and pUGD0600 (supplied by Dr. S. Mizuno) which is W chromosome specific in chickens, were tested for sex specificity in Oreochromis niloticus. Results from hybridizations of these probes to Southern blotted digests of O.niloticus DNA are reported. Both probes hybridized to O.niloticus genomic DNA but neither gave sex specific patterns. Four short repeat oligonucleotide sequences were synthesized. Two sequences were labelled both non-radioactively, with dioxygenin and with 32P and were used to probe Southern blots of O.niloticus DNA and dried agarose gels containing O.niloticus DNA. The probes (GATA)4(GACA)1 and (GATA)3(GACA)2 both gave fingerprint like patterns but no sex specific banding patterns were observed. The implications of these results for the organization of repetitive sequences in the O.niloticus genome are discussed. A partial DNA library, enriched for male specific sequences was created by subtractive hybridization using the Phenol Emulsion Reassociation Technique (PERT). Thirteen recombinant colonies containing inserts were isolated. Inserts from the library were screened for sex specificity. Two inserts were partially sequenced and PCR primers for them were constructed which were used to amplify the sequences in genomic DNA. Both sequences were successfully amplified from genomic DNA but neither was male specific. The amplified sequences were restricted with a number of restriction enzymes to identify sex specific restriction fragment length polymorphisms (RFLPs) but, again, none were observed. Sequences were also tested for similarity to sequences in the EMBL/GENBANK nucleotide databases using the suite of programs available on SEQNET (Daresbury laboratory). Future approaches to the isolation of sex specific DNA sequences in the Tilapias are discussed in detail.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available