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Identifier uch.biology.phd//2001ladoukakis
Title Ο Ομόλογος ανασυνδυασμός στο μιτοχονδριακό DNA των ζώων
Alternative Title Homologous recombination in animal mitochondrial DNA
Author Λαδουκάκης, Εμμανουήλ
Thesis advisor Ζούρος, Ελευθέριος
Abstract In the present work evidence is presented for recombination in animal mtDNA from two sources: direct results from mussels and from the literature. a) Mussel males inherit an mtDNA genome from their mother (genome F) and one from the father (genome M). In the majority of cases the two molecules differ by more than 20% in sequence, but occasionally the paternal genome may be very similar to maternal. Males of the latter type were examined and recombinant molecules recovered in four out of ten. The gonadal tissues of these males were polyplasmic apparently because of recombination. Within the examined 681 bp of a segment of the COIII gene, exchanged fragments varied from 24 to 255 bp or larger. The possibility that the results were due to "PCR jumping" was excluded by specially designed experiments i) In the first experiment cloned paternal sequences were offered to DNA polymerase but no recombinant molecules was produced in vitro ii) Special primers were designed to recover the same recombinant sequences from gonadal DNA pool. Cloning of PCR product from typical males revealed that recombination can happened also between F and M molecules. b) A non-systematic search of the literature was done for signs of historical recombination. DNA sequences were first converted into amino acid sequences on the rational that the signature of recombination would be more conserved in the amino acid sequence. Three cases (one crustacean Gammarus fossarum, one amphibian of the genus Rana and one mammal, of the genus Apodemus) were recovered where comparisons of amino acid sequences were very suggestive of recombination. We then returned to DNA sequences and asked if the similarities between putatively exchanged regions could be explained by chance and found that this chance is extremely low. Three statistical experiments were designed to verify that the recombination was happened and to define the length of the swaped fragment. Sliding windows and random suffling experiments prooved that recombination can explain the diversity of the sequences. Sliding windows with variable size of the window showed the length of the swapped fragment.
Language Greek
Subject Ανασυνδυασμός; DNA, Μιτοχονδριακό (M+DNA); Ετεροπλασμία; Κλώνος; Ζώα; Γονιδιακή μετατροπή
Issue date 2001-06-21
Collection   School/Department--School of Sciences and Engineering--Department of Biology--Doctoral theses
  Type of Work--Doctoral theses
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