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Cytogenetic studies of the genus Tettigonia (Orthoptera, Tettigonioidea, Tettigoniinae).II.Heteromorphism of C-bands

100%

Warchalowska-Sliwa E., Maryanska-Nadachowska A.

Folia Biologica

1995

vol. 43

issue 3-4

99-106

Heteromorphism of distal C-bands of differnet origin connected with the M2 bivalent was observed in four analysed species, i.e.Tettigonia cantans, Tettigonia viridissima, Tettigonia caudata and Tettigonia ussuriana.Study of the chiasma distribution showed that presence of heteromorphic segments significantly modified this pattern, and hiasma formed preferentially in the chromosomal region furthest from the heteromorphic segment.Additionally, in the M3 bivalent of Tettigoni cantans, in the L1 of Tettigonia viridissima, and in the X chromosome of Tettigonia cantans, Tettigonia viridissima and Tettigonia caudata variability of the distal segment was observed.

Chromosome abnormalities without phenotypic consequences

88%

Kowalczyk M., Srebniak M., Tomaszewska A.

Journal of Applied Genetics

2007

vol. 48

issue 2

157-166

Some changes in chromosome morphology, detected during cytogenetic analysis, are not associated with clinical defects. Therefore a proper discrimination of harmless variants from true abnormalities, especially during prenatal diagnosis, is crucial to allow precise counseling. In this review we described chromosome variants and examples of chromosome anomalies that are considered to be unrelated to phenotypic consequences. The correlation between the presence of marker chromosomes and a risk of clinical signs is also discussed. Structural rearrangements of heterochromatic material, satellite polymorphism, or fragile sites, are well-known examples of common chromosome variation. However, the absence of clinical effects has also been reported in some cases of chromosome abnormalities concerning euchromatin. Such euchromatic anomalies were divided into 2 categories: unbalanced chromosome abnormalities (UBCAs), such as deletions or duplications, and euchromatic variants (EVs). Recently so-called molecular karyotyping, especially whole-genome screening by the use of high-resolution array-CGH technique, contributed to revealing a high number of previously unknown small genomic variations, which seem to be asymptomatic, as they are present in phenotypically normal individuals.

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1 Folia Biologica

1 Journal of Applied Genetics

1 2007

1 1995

1 Kowalczyk M.

1 Maryanska-Nadachowska A.

1 Srebniak M.

1 Tomaszewska A.

1 Warchalowska-Sliwa E.

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Cytogenetic studies of the genus Tettigonia (Orthoptera, Tettigonioidea, Tettigoniinae).II.Heteromorphism of C-bands

Chromosome abnormalities without phenotypic consequences