Aberrant meioses in diploid and triploid progeny of gynogenetic diploids produced from eggs of natural tetraploid loach, Misgurnus anguillicaudatus
2002
Zhang, Q. (Ocean Univ., Qingdao (China). Marine Life Science Coll.) | Hanada, K. | Arai, K.
Gynogenetic diploids were produced from the eggs of natural tetraploid loach Misgurnus anguillicaudatus without any manipulation for chromosome duplication. When eggs of a four-year-old diploid gynogenetic individual were fertilized with spermatozoa of specimens from normal diploid and natural tetraploid lines, viable diploid and triploid progeny were produced, respectively. In the gonads of diploid progeny, diploid (2n=50) and tetraploid (4n=100) mitotic metaphases were observed. The majority of oocytes (76 %) showed regular 25 bivalents as in normal diploids. A few spermatocytes (6 %) showed normal 25 bivalents, but 86 % contained various number of univalents. In the triploid progeny, triploid and hexaploid mitotic metaphases were observed in both ovaries and testes. Most meiotic figures (about 90 %) contained approximately 75 or more bivalents. Spermatozoa were not identified in the testis by flow cytometry. The diploid males between the diploid gynogens and common diploid, and both sexes of triploids between the diploid gynogens and tetraploid, show aberrant meioses such as frequent formation of univalents, but the diploid females seem to be less affected.
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