scholarly journals Chromosomes, Nuclear Genes and the Phylogenetic Placement Within the Reptilia of Sphenodon (Tuatara)

2021 ◽  
Author(s):  
◽  
Thomas Bruce Norris
Keyword(s):  
Common Ancestor ◽  
Nuclear Dna ◽  
Chromosome Morphology ◽  
Comparative Genomic Hybridisation ◽  
Comparative Genomic ◽  
Chromosome 11 ◽  
Telomeric Sequences ◽  
Phylogenetic Placement ◽  
Dna Analyses ◽  
North Eastern

<p>Chromosomes were examined from five populations of Sphenodon (tuatara)  using giemsa, Ag-NOR, C-, G- and RE- banding. There were no differences between species, populations or sexes, although one animal had a structural heteromorphism. Chromosome morphology homology to Testudines (turtles), Aves (birds) and to a lesser extent Crocodylia (crocodiles) allowed reconstruction ofa Reptilian proto-karyotype, dated to 300 million years ago. DNA sequence was isolated from the WT1, AMH, DMRT1, FoxG1 and 28S. No variation was present in Sphenodon 28S, FoxG1 or AMH sequence. 28S could be dated to a common ancestor with Testudines, similar to the archaic karyotype. FoxG1 and AMH reflect an Oligocene divergence, WT1 divides north-eastern North Island and Cook Strait, and can be dated to the Pleistocene or the Pliocene, and DMRT1appears a recent post- pliocene divergence. FISH localised DIG-labelled probes of AMH to chromosome 11 and WT1 to chromosome 13 or 14. Human telomeric probes localised to Sphenodon telomeric regions demonstrating the highly conserved nature of telomeric sequences. Comparative genomic hybridisation with chicken chromosomes did not produce any regions of homology, implying significant chromosomal and DNA changes since the Orders shared a common ancestor, although macrochromosome morphology has remained similar. Sphenodon chromosomal and nuclear DNA analyses demonstrate evolutionary decoupling, supporting recent mtDNA work.</p>

scholarly journals Chromosomes, Nuclear Genes and the Phylogenetic Placement Within the Reptilia of Sphenodon (Tuatara)

2021 ◽  
Author(s):  
◽  
Thomas Bruce Norris
Keyword(s):  
Common Ancestor ◽  
Nuclear Dna ◽  
Chromosome Morphology ◽  
Comparative Genomic Hybridisation ◽  
Comparative Genomic ◽  
Chromosome 11 ◽  
Telomeric Sequences ◽  
Phylogenetic Placement ◽  
Dna Analyses ◽  
North Eastern

<p>Chromosomes were examined from five populations of Sphenodon (tuatara)  using giemsa, Ag-NOR, C-, G- and RE- banding. There were no differences between species, populations or sexes, although one animal had a structural heteromorphism. Chromosome morphology homology to Testudines (turtles), Aves (birds) and to a lesser extent Crocodylia (crocodiles) allowed reconstruction ofa Reptilian proto-karyotype, dated to 300 million years ago. DNA sequence was isolated from the WT1, AMH, DMRT1, FoxG1 and 28S. No variation was present in Sphenodon 28S, FoxG1 or AMH sequence. 28S could be dated to a common ancestor with Testudines, similar to the archaic karyotype. FoxG1 and AMH reflect an Oligocene divergence, WT1 divides north-eastern North Island and Cook Strait, and can be dated to the Pleistocene or the Pliocene, and DMRT1appears a recent post- pliocene divergence. FISH localised DIG-labelled probes of AMH to chromosome 11 and WT1 to chromosome 13 or 14. Human telomeric probes localised to Sphenodon telomeric regions demonstrating the highly conserved nature of telomeric sequences. Comparative genomic hybridisation with chicken chromosomes did not produce any regions of homology, implying significant chromosomal and DNA changes since the Orders shared a common ancestor, although macrochromosome morphology has remained similar. Sphenodon chromosomal and nuclear DNA analyses demonstrate evolutionary decoupling, supporting recent mtDNA work.</p>

scholarly journals Involvement of the MEN1 gene locus in familial isolated hyperparathyroidism

2002 ◽  
pp. 313-322 ◽  
Author(s):  
A Villablanca ◽  
WS Wassif ◽  
T Smith ◽  
A Hoog ◽  
O Vierimaa ◽  
...  
Keyword(s):  
Multiple Endocrine Neoplasia Type ◽  
Suppressor Gene ◽  
Tumour Suppressor Gene ◽  
Comparative Genomic Hybridisation ◽  
Comparative Genomic ◽  
Wild Type ◽  
Chromosome 11 ◽  
Men1 Gene ◽  
Parathyroid Disease

BACKGROUND: Familial isolated hyperparathyroidism (FIHP) is a hereditary disorder characterised by uni- or multiglandular parathyroid disease. A subset of families are likely to be genetic variants of other familial tumour syndromes in which PHPT is the main feature, for example multiple endocrine neoplasia type 1 (MEN 1) and the hyperparathyroidism-jaw tumour syndrome (HPT-JT). OBJECTIVE: To investigate seven families diagnosed with FIHP, each with two to eight affected family members, to clarify the underlying genetic mechanism. METHODS: The entire MEN1 gene was sequenced for germline mutations and, in addition, tumour specimens were analysed in comparative genomic hybridisation and loss of heterozygosity studies. RESULTS: Two families exhibited MEN1 mutations, L112V and 1658delG, which were associated with loss of the wild-type 11q13 alleles in all tumours analysed. In the remaining five families, no MEN1 mutation was identified. CONCLUSION: These results support the involvement of the MEN1 tumour suppressor gene in the pathogenesis of some of the FIHP kindreds. However, loss on chromosome 11 was seen in all tumours exhibiting somatic deletions, although in two families the tumour deletions involved 11q distal to MEN1. We conclude that the altered MEN1 gene function is of importance in the development of FIHP.

scholarly journals Cytogenetically Elusive Sex Chromosomes in Scincoidean Lizards

2021 ◽  
Vol 22 (16) ◽  
pp. 8670
Author(s):  
Alexander Kostmann ◽  
Barbora Augstenová ◽  
Daniel Frynta ◽  
Lukáš Kratochvíl ◽  
Michail Rovatsos
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Morphology ◽  
Comparative Genomic ◽  
Morphological Divergence ◽  
Telomeric Sequences ◽  
Molecular Cytogenetic ◽  
Interstitial Telomeric Sequences ◽  
Rdna Loci ◽  
Cytogenetic Methods

The lizards of the species-rich clade Scincoidea including cordylids, gerrhosaurids, skinks, and xantusiids, show an almost cosmopolitan geographical distribution and a remarkable ecological and morphological divergence. However, previous studies revealed limited variability in cytogenetic traits. The sex determination mode was revealed only in a handful of gerrhosaurid, skink, and xantusiid species, which demonstrated either ZZ/ZW or XX/XY sex chromosomes. In this study, we explored the karyotypes of six species of skinks, two species of cordylids, and one gerrhosaurid. We applied conventional and molecular cytogenetic methods, including C-banding, fluorescence in situ hybridization with probes specific for telomeric motifs and rDNA loci, and comparative genomic hybridization. The diploid chromosome numbers are rather conserved among these species, but the chromosome morphology, the presence of interstitial telomeric sequences, and the topology of rDNA loci vary significantly. Notably, XX/XY sex chromosomes were identified only in Tiliqua scincoides, where, in contrast to the X chromosome, the Y chromosome lacks accumulations of rDNA loci. We confirm that within the lizards of the scincoidean clade, sex chromosomes remained in a generally poor stage of differentiation.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

De novo monosomy 9p24.3-pter and trisomy 17q24.3-qter characterised by microarray comparative genomic hybridisation in a fetus with an increased nuchal translucency

2006 ◽  
Vol 26 (3) ◽  
pp. 206-213 ◽  
Author(s):  
Sophie Brisset ◽  
Serdar Kasakyan ◽  
Aurore Coulomb L'Herminé ◽  
Valérie Mairovitz ◽  
Evelyne Gautier ◽  
...  
Keyword(s):  
De Novo ◽  
Nuchal Translucency ◽  
Comparative Genomic Hybridisation ◽  
Comparative Genomic ◽  
Increased Nuchal Translucency

Development of a genomic predictive model for cholangiocarcinoma using copy number alteration data

2021 ◽  
pp. jclinpath-2020-207346
Author(s):  
Inês Tavares ◽  
Ricardo Martins ◽  
Ilda Patrícia Ribeiro ◽  
Luísa Esteves ◽  
Francisco Caramelo ◽  
...  
Keyword(s):  
Survival Analysis ◽  
Copy Number ◽  
Patient Management ◽  
Copy Number Alteration ◽  
Comparative Genomic Hybridisation ◽  
Support Vector ◽  
Comparative Genomic ◽  
Support Vector Machine Algorithm ◽  
Rare Tumour ◽  
Genomic Model

AimsCholangiocarcinoma (CC) is a rare tumour arising from the biliary tract epithelium. The aim of this study was to perform a genomic characterisation of CC tumours and to implement a model to differentiate extrahepatic (ECC) and intrahepatic (ICC) cholangiocarcinoma.MethodsDNA extracted from tumour samples of 23 patients with CC, namely 10 patients with ECC and 13 patients with ICC, was analysed by array comparative genomic hybridisation. A support vector machine algorithm for classification was applied to the genomic data to distinguish between ICC and ECC. A survival analysis comparing both groups of patients was also performed.ResultsWith these whole genome results, we observed several common alterations between tumour samples of the same CC anatomical type, namely gain of Xp and loss of 3p, 11q11, 14q, 16q, Yp and Yq in ICC tumours, and gain of 16p25.3 and loss of 3q26.1, 6p25.3–22.3, 12p13.31, 17p, 18q and Yp in ECC tumours. Gain of 2q37.3 was observed in the samples of both tumour subtypes, ICC and ECC. The developed genomic model comprised four chromosomal regions that seem to enable the distinction between ICC and ECC, with an accuracy of 71.43% (95% CI 43% to 100%). Survival analysis revealed that in our cohort, patients with ECC survived on average 8 months less than patients with ICC.ConclusionsThis genomic characterisation and the introduction of genomic models to clinical practice could be important for patient management and for the development of targeted therapies. The power of this genomic model should be evaluated in other CC populations.

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