Authors: Dorota Juchno Olga Jabłońska Alicja Boroń Roman Kujawa Anna Leska Anna Grabowska Anna Nynca Sylwia Świgońska Magdalena Król Aneta Spóz Natalia Laskowska Miłosz Lao
Publish Date: 2014/07/24
Volume: 142, Issue: 4, Pages: 351-359
Abstract
Crosses between 21 triploid hybrid Cobitis females and 19 C taenia 2n = 48 males led to viable progeny whereas no embryonic development was observed in crosses with tetraploid males 4n = 98 The ploidy status of 491 progenies randomly selected with flow cytometry 316 or chromosome analysis 175 revealed an average of 552 triploids and 448 tetraploids but the ratio of 3n versus 4n fish did change during development In the first 2 days after hatching approximately 651 of tetraploid larvae were observed Their number decreased significantly to 308 and 62 on average during 2–5 and 10–15 months of life respectively The karyotype of tetraploid progeny 4n = 98 included 3n = 74 chromosomes of the parental female and n = 24 of C taenia male The number of tetraploid progeny indicated indirectly that about 66 of eggs from 3n females were fertilized with C taenia The rest of the eggs developed clonally via gynogenesis or hemiclonally via hybridogenesis into triploids of the same karyotype structure as parental females We have documented for the first time that at least under experimental conditions tetraploids are commonly formed but are less viable than triploids and a ratio similar to what is found under natural conditions is finally attained The current explanation concerning the ploidy and karyotype structure of the progeny confirms that the eggs of 3n Cobitis females are not only capable of maintaining all chromosomes but are also capable of incorporating the sperm genome thus creating the potential to produce tetraploidsWe would like to express our sincere thanks to dr Slawomir Boroń for fish collecting This work was supported by The National Science Centre Poland Grant number N N303 068834 and The University of Warmia and Mazury in Olsztyn Grant number 0208806
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