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7
result(s) for
"Wey-Fabrizius, Alexandra"
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Platyzoan Paraphyly Based on Phylogenomic Data Supports a Noncoelomate Ancestry of Spiralia
2014
Based on molecular data three major clades have been recognized within Bilateria: Deuterostomia, Ecdysozoa, and Spiralia. Within Spiralia, small-sized and simply organized animals such as flatworms, gastrotrichs, and gnathostomulids have recently been grouped together as Platyzoa. However, the representation of putative platyzoans was low in the respective molecular phylogenetic studies, in terms of both, taxon number and sequence data. Furthermore, increased substitution rates in platyzoan taxa raised the possibility that monophyletic Platyzoa represents an artifact due to long-branch attraction. In order to overcome such problems, we employed a phylogenomic approach, thereby substantially increasing 1) the number of sampled species within Platyzoa and 2) species-specific sequence coverage in data sets of up to 82,162 amino acid positions. Using established and new measures (long-branch score), we disentangled phylogenetic signal from misleading effects such as long-branch attraction. In doing so, our phylogenomic analyses did not recover a monophyletic origin of platyzoan taxa that, instead, appeared paraphyletic with respect to the other spiralians. Platyhelminthes and Gastrotricha formed a monophylum, which we name Rouphozoa. To the exclusion of Gnathifera, Rouphozoa and all other spiralians represent a monophyletic group, which we name Platytrochozoa. Platyzoan paraphyly suggests that the last common ancestor of Spiralia was a simple-bodied organism lacking coelomic cavities, segmentation, and complex brain structures, and that more complex animals such as annelids evolved from such a simply organized ancestor. This conclusion contradicts alternative evolutionary scenarios proposing an annelid-like ancestor of Bilateria and Spiralia and several independent events of secondary reduction.
Journal Article
Transcriptome Data Reveal Syndermatan Relationships and Suggest the Evolution of Endoparasitism in Acanthocephala via an Epizoic Stage
by
Hankeln, Thomas
,
Herlyn, Holger
,
Wey-Fabrizius, Alexandra R.
in
Acanthocephala
,
Acanthocephala - genetics
,
Acanthocephala - growth & development
2014
The taxon Syndermata comprises the biologically interesting wheel animals (\"Rotifera\": Bdelloidea + Monogononta + Seisonidea) and thorny-headed worms (Acanthocephala), and is central for testing superordinate phylogenetic hypotheses (Platyzoa, Gnathifera) in the metazoan tree of life. Recent analyses of syndermatan phylogeny suggested paraphyly of Eurotatoria (free-living bdelloids and monogononts) with respect to endoparasitic acanthocephalans. Data of epizoic seisonids, however, were absent, which may have affected the branching order within the syndermatan clade. Moreover, the position of Seisonidea within Syndermata should help in understanding the evolution of acanthocephalan endoparasitism. Here, we report the first phylogenomic analysis that includes all four higher-ranked groups of Syndermata. The analyzed data sets comprise new transcriptome data for Seison spec. (Seisonidea), Brachionus manjavacas (Monogononta), Adineta vaga (Bdelloidea), and Paratenuisentis ambiguus (Acanthocephala). Maximum likelihood and Bayesian trees for a total of 19 metazoan species were reconstructed from up to 410 functionally diverse proteins. The results unanimously place Monogononta basally within Syndermata, and Bdelloidea appear as the sister group to a clade comprising epizoic Seisonidea and endoparasitic Acanthocephala. Our results support monophyly of Syndermata, Hemirotifera (Bdelloidea + Seisonidea + Acanthocephala), and Pararotatoria (Seisonidea + Acanthocephala), rejecting monophyly of traditional Rotifera and Eurotatoria. This serves as an indication that early acanthocephalans lived epizoically or as ectoparasites on arthropods, before their complex lifecycle with arthropod intermediate and vertebrate definite hosts evolved.
Journal Article
Clinically relevant variants in a large cohort of Indian patients with Marfan syndrome and related disorders identified by next-generation sequencing
by
Wey-Fabrizius, Alexandra
,
Maiya, Shreesha
,
Meester, Josephina
in
631/208
,
631/208/2489
,
631/208/2489/144
2021
Marfan syndrome and related disorders are a group of heritable connective tissue disorders and share many clinical features that involve cardiovascular, skeletal, craniofacial, ocular, and cutaneous abnormalities. The majority of affected individuals have aortopathies associated with early mortality and morbidity. Implementation of targeted gene panel next-generation sequencing in these individuals is a powerful tool to obtain a genetic diagnosis. Here, we report on clinical and genetic spectrum of 53 families from India with a total of 83 patients who had a clinical diagnosis suggestive of Marfan syndrome or related disorders. We obtained a molecular diagnosis in 45/53 (85%) index patients, in which 36/53 (68%) had rare variants in
FBN1
(Marfan syndrome; 63 patients in total), seven (13.3%) in
TGFBR1
/
TGFBR2
(Loeys–Dietz syndrome; nine patients in total) and two patients (3.7%) in
SKI
(Shprintzen–Goldberg syndrome). 21 of 41 rare variants (51.2%) were novel. We did not detect a disease-associated variant in 8 (15%) index patients, and none of them met the Ghent Marfan diagnostic criteria. We found the homozygous
FBN1
variant p.(Arg954His) in a boy with typical features of Marfan syndrome. Our study is the first reporting on the spectrum of variants in
FBN1, TGFBR1, TGFBR2
, and
SKI
in Indian individuals.
Journal Article
Next-generation sequencing of 32 genes associated with hereditary aortopathies and related disorders of connective tissue in a cohort of 199 patients
2019
Purpose
Heritable factors play an important etiologic role in connective tissue disorders (CTD) with vascular involvement, and a genetic diagnosis is getting increasingly important for gene-tailored, personalized patient management.
Methods
We analyzed 32 disease-associated genes by using targeted next-generation sequencing and exome sequencing in a clinically relevant cohort of 199 individuals. We classified and refined sequence variants according to their likelihood for pathogenicity.
Results
We identified 1 pathogenic variant (PV; in
FBN1
or
SMAD3
) in 15 patients (7.5%) and ≥1 likely pathogenic variant (LPV; in
COL3A1
,
FBN1
,
FBN2
,
LOX
,
MYH11
,
SMAD3
,
TGFBR1
, or
TGFBR2
) in 19 individuals (9.6%), together resulting in 17.1% diagnostic yield. Thirteen PV/LPV were novel. Of PV/LPV-negative patients 47 (23.6%) showed ≥1 variant of uncertain significance (VUS). Twenty-five patients had concomitant variants. In-depth evaluation of reported/calculated variant classes resulted in reclassification of 19.8% of variants.
Conclusion
Variant classification and refinement are essential for shaping mutational spectra of disease genes, thereby improving clinical sensitivity. Obligate stringent multigene analysis is a powerful tool for identifying genetic causes of clinically related CTDs. Nonetheless, the relatively high rate of PV/LPV/VUS-negative patients underscores the existence of yet unknown disease loci and/or oligogenic/polygenic inheritance.
Journal Article