The origin of spontaneous heteroploids in the progeny of diploid, triploid, and tetraploid axolotl females

Fankhauser, Gerhard; Humphrey, R. R.

doi:10.1002/jez.1401420118

Cited by 31 publications

(2 citation statements)

References 40 publications

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“…If such methods can be applied to produce autotetraploids of R. nigromaculata , it is interesting to analyze the chromosome numbers of the offspring of autotetraploids to compare the incidence of the aneuploids among tetraploid tadpoles produced by different methods. Autotetraploid males from the species A. mexicanum (Humphrey and Fankhauser, 1956;Fankhauser and Humphrey, 1959) and X. laevis (Gurdon, 1959) were completely sterile. Among tetraploid silkworms obtained by Vereiskaya and Astaurov (1962), amphidiploid females derived from matings between Bombyx mori and B. mandarina were as fertile as autotetraploid females of B. mori , while amphidiploid males from the same parentage were partly fertile, and autotetraploid males were completely sterile.…”

Section: Discussionmentioning

confidence: 98%

Developmental Capacity and Chromosome Number in the Offspring of Artificially Produced Autotetraploids of Rana nigromaculata

Kondo

2002

Zoological Science

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A large number of autotetraploids of Rana nigromaculata were produced in order to assess their developmental capacity and chromosome number in their offspring. An original autotetraploid male was first produced by transplanting a nucleus from an embryo (triploid) into an unfertilized egg. Next, eggs were inseminated with sperm of the autotetraploid male, then cold-treated to obtain first-, second-, and third-generation offspring. According to an investigation of the chromosome numbers of the tadpoles by the tail-tip squash method, the three generations of offspring included many tetraploids (50-80%), as well as some diploids, triploids, hexaploids and mosaics at the early tadpole stage. In addition, several percent of the second-and third-generation offspring were found to be aneuploids. Evidently, a complete set of diploid chromosomes was not precisely transferred to all of the next-generation offspring from the sperm of the artificially produced autotetraploid males. These observations suggest that there were some abnormalities in the course of spermatogenesis in the male autotetraploid frogs.

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Section: Discussionmentioning

confidence: 98%

Developmental Capacity and Chromosome Number in the Offspring of Artificially Produced Autotetraploids of Rana nigromaculata

Kondo

2002

Zoological Science

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“…Somatic interphase nuclei of Nn heterozygotes, provided the nucleoli are not fused, generally contain two nucleoli of markedly different size, and the heterozygotes can be readily distinguished from either homozygote by this character. Fankhauser & Humphrey (1959) had earlier shown that the white mutant d, whose dominant normal allele D determines dark skin colour, lies on the nucleolarorganizing chromosome, and they gave evidence supporting the view that the locus for D (or d) lies close to the nucleolar organizer.…”

Section: The Nucleolar Organizer In Oocytesmentioning

confidence: 88%

Chromosomes and nucleoli of the axolotl, Ambystoma mexicanum

Callan

1966

Journal of Cell Science

138

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Amongst the axolotl's haploid complement of fourteen mitotic chromosomes, one of the four largest, with a greater arm asymmetry than the other three, shows a nucleolar constriction subterminally in its shorter arm. Low-temperature treatment causes further secondary constrictions to appear; these constrictions enable most of the mitotic chromosomes to be identified; the constrictions occur at similar sites in the chromosomes of tail-fin epithelial cells, hepatocytes, and brain cells. Homology between the mitotic and oocyte (lampbrush) nucleolar organizers has been established, and thus the several hundred free nucleoli in oocytes are genetically related to the two nucleoli of diploid somatic interphases. During oocyte development the free nucleoli transform from solid structures to rings and back to solid structures again without detectable increase in number. During the contraction and aggregation of the lampbrush chromosomes within the oocyte nucleus as maturity approaches, in most axolotls the free ring-shaped nucleoli become stretched between the nuclear periphery and central chromosome group, and take on a characteristic beaded appearance. These transformations of the free nucleoli are largely paralleled by forms which nucleoli attached subterminally to the shorter arm of lampbrush chromosome III concurrently assume. The question as to whether fully developed nucleoli detach from the organizer loci and add to the population of free nucleoli in oocytes remains undecided. It may well be that virtually all the DNA-generators of free nucleoli detach from the organizer loci before starting to carry out nucleolar functions, and before there is any significant accumulation of protein and RNA around them. If so, the variability in quantity of attached nucleolar material may not reflect different states in a nucleolar synthesis and detachment cycle, but rather variation in the number of nucleolar DNA Anlagen which happen to remain attached to the organizer loci after the synthesis and detachment of the great majority of the Anlagen has ceased. In occasional oocytes the only chromosomal continuity maintained across the organizer locus consists of a nucleolar ‘double bridge’; this indicates that the genetically persistent (i.e. chromosomal) organizer DNA bears the same structural relationship to neighbouring parts of a lampbrush chromosome as any other chromomere with its attendant pair of lateral loops. The lampbrush chromosomes of the axolotl have been provisionally mapped. The centromeres are represented by short portions of chromosome axis without lateral loops, and there are two spheres close to the centromeres of both chromosome VI and chromosome XIII. Other recognition characters are inconspicuous or not very reliable, and features of the lampbrush chromosomes related to the low-temperature induced secondary constrictions of mitotic chromosomes have not been identified.

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Chromosomal and Other Genetic Influences on Birth Weight Variation

Polanl¹

1974

Novartis Foundation Symposia

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The origin of spontaneous heteroploids in the progeny of diploid, triploid, and tetraploid axolotl females

Cited by 31 publications

References 40 publications

Developmental Capacity and Chromosome Number in the Offspring of Artificially Produced Autotetraploids of Rana nigromaculata

Developmental Capacity and Chromosome Number in the Offspring of Artificially Produced Autotetraploids of Rana nigromaculata

Chromosomes and nucleoli of the axolotl, Ambystoma mexicanum

Chromosomal and Other Genetic Influences on Birth Weight Variation

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