Euchromatic Supernumerary Chromosomal Segments—Remnants of Ongoing Karyotype Restructuring in the Prospero autumnale Complex?

Supernumerary chromosomal segments (SCSs) represent additional chromosomal material that, unlike B chromosomes, is attached to the standard chromosome complement. The Prospero autumnale complex (Hyacinthaceae) is polymorphic for euchromatic large terminal SCSs located on the short arm of chromosome 1 in diploid cytotypes AA and B7B7, and tetraploid AAB7B7 and B6B6B7B7, in addition to on the short arm of chromosome 4 in polyploid B7B7B7B7 and B7B7B7B7B7B7 cytotypes. The genomic composition and evolutionary relationships among these SCSs have been assessed using fluorescence in situ hybridisation (FISH) with 5S and 35S ribosomal DNAs (rDNAs), satellite DNA PaB6, and a vertebrate-type telomeric repeat TTAGGG. Neither of the rDNA repeats were detected in SCSs, but most contained PaB6 and telomeric repeats, although these never spanned whole SCSs. Genomic in situ hybridisation (GISH) using A, B6, and B7 diploid genomic parental DNAs as probes revealed the consistently higher genomic affinity of SCSs in diploid hybrid B6B7 and allopolyploids AAB7B7 and B6B6B7B7 to genomic DNA of the B7 diploid cytotype. GISH results suggest a possible early origin of SCSs, especially that on chromosome 1, as by-products of the extensive genome restructuring within a putative ancestral P. autumnale B7 genome, predating the complex diversification at the diploid level and perhaps linked to B-chromosome evolution.

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Analysis of aneuploidy for chromosomes 13, 21, X and Y by multicolour fluorescence in situ hybridisation (FISH) in a 47,XYY male

Zygote ◽

10.1017/s0967199499000489 ◽

1999 ◽

Vol 7 (2) ◽

pp. 131-134 ◽

Cited By ~ 20

Author(s):

Renée H. Martin ◽

Brenda McInnes ◽

A.W. Rademaker

Keyword(s):

Y Chromosome ◽

Sex Chromosomes ◽

In Situ Hybridisation ◽

Chromosome 1 ◽

Fluorescence In Situ Hybridisation ◽

Chromosome 13 ◽

Normal Men ◽

Diploid Sperm

The frequency of aneuploid sperm was assessed by fluorescence in situ hybridisation (FISH) in a 47,XYY male previously studied by sperm karyotyping. A total of 20 021 sperm were studied: 10 017 by two-colour FISH for chromosomes 13 and 21 and 10 002 by three-colour FISH for the sex chromosomes using chromosome 1 as an autosomal control for diploidy and lack of hybridisation. Results were compared with more than 500 000 sperm from 18 normal men. The frequencies of X-bearing (49.4%) and Y-bearing sperm (49.8%) were not significantly different from 50% as shown in our sperm karyotyping study. There was no significant increase in the frequency of diploid sperm compared with control donors. There was a significant increase in the frequency of disomy for chromosome 13 (p<0.0001) and XY disomy (p=0.0008) compared with control donors. However, since the frequency of disomy was 0.40% for chromosome 13 and 0.55% for XY disomy, it is not surprising that these increases were not discovered previously in our analysis of 75 sperm karyotypes. Our results suggest that the extra Y chromosome is eliminated during spermatogenesis in the majority of cells but that there may be a small but significant increase in the frequency of aneuploid sperm in these men.

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Rapid Multi-Hybridisation FISH Screening for Balanced Porcine Reciprocal Translocations Suggests a Much Higher Abnormality Rate Than Previously Appreciated

Cells ◽

10.3390/cells10020250 ◽

2021 ◽

Vol 10 (2) ◽

pp. 250

Author(s):

Rebecca E O’Connor ◽

Lucas G Kiazim ◽

Claudia C Rathje ◽

Rebecca L Jennings ◽

Darren K Griffin

Keyword(s):

Semen Analysis ◽

In Situ Hybridisation ◽

Economic Loss ◽

Environmental Damage ◽

Fluorescence In Situ Hybridisation ◽

Reciprocal Translocations ◽

Chromosome Translocations ◽

Farrowing Rate ◽

Significant Economic Loss

With demand rising, pigs are the world’s leading source of meat protein; however significant economic loss and environmental damage can be incurred if boars used for artificial insemination (AI) are hypoprolific (sub-fertile). Growing evidence suggests that semen analysis is an unreliable tool for diagnosing hypoprolificacy, with litter size and farrowing rate being more applicable. Once such data are available, however, any affected boar will have been in service for some time, with significant financial and environmental losses incurred. Reciprocal translocations (RTs) are the leading cause of porcine hypoprolificacy, reportedly present in 0.47% of AI boars. Traditional standard karyotyping, however, relies on animal specific expertise and does not detect more subtle (cryptic) translocations. Previously, we reported development of a multiple hybridisation fluorescence in situ hybridisation (FISH) strategy; here, we report on its use in 1641 AI boars. A total of 15 different RTs were identified in 69 boars, with four further animals XX/XY chimeric. Therefore, 4.5% had a chromosome abnormality (4.2% with an RT), a 0.88% incidence. Revisiting cases with both karyotype and FISH information, we reanalysed captured images, asking whether the translocation was detectable by karyotyping alone. The results suggest that chromosome translocations in boars may be significantly under-reported, thereby highlighting the need for pre-emptive screening by this method before a boar enters a breeding programme.

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