Polycelis nigrcl is a free-living simultaneous hermaphroditic flatworm that has amphimictic and pseudogamous parthenogenetic biotypes. Sexual individuals are always diploid (2n = 16) and pseudogamous parthenogens are polyploid (usually triploid). Two types of supernumerary chromosomes are found in parthenogens, those resembling autosomes ("A-like") and typical B chromosomes, both of which reach...

B chromosomes are apparently dispensable components found in the genomes of many species that are mainly composed of repetitive DNA sequences. Among the numerous questions concerning B chromosomes, the origin of these elements has been widely studied. To date, supernumerary chromosomes have been identified in approximately 60 species of fish, including species of the genus Characidium Reinhardt...

The interpretation of supernumerary chromosome is important for genetic counseling and prognosis. Here, we used SNP array and conventional karyotyping method to identify a denovo marker chromosome originated from chromosome 22 and 11 in a newborn transferred to the Neonatal Intensive Care Unit of Shahid Sadoughi Hospital in 2015. Clinical abnormalities identified in the newborn were dysmorphic ...

Here we report on three new patients with neocentric small supernumerary marker chromosomes (sSMC) derived from chromosome 2, 13 and 15, respectively. The sSMC(13) and sSMC(15) had inverted duplicated shapes and the sSMC(2) a ring chromosome shape. All three cases were clinically severely abnormal. A review of the available sSMC literature revealed that up to the present 73 neocentric sSMC case...

We characterized three supernumerary marker chromosomes (SMCs) simultaneously present in a 2-year- and 10-month-old male patient with mental retardation and dysmorphic features. Peripheral blood chromosome analysis revealed two to three SMCs in 25/26 cells analyzed. The remaining one cell had one SMC. Microarray comparative genomic hybridization (aCGH) showed mosaicism for gains of 5q35.3, 15q1...

Uniparental disomy (UPD) describes the inheritance of a pair of chromosomes from only one parent. Mechanisms of formation are trisomy rescue, monosomy rescue, post-fertilisation errors, and gamete complementation. Problems associated with UPD include trisomy mosaicism, genomic imprinting, homozygosity of autosomal recessive mutations, or even a combination of these. Supernumerary marker chromos...

Uniparental disomy (UPD) describes the inheritance of a pair of chromosomes from only one parent. Mechanisms of formation are trisomy rescue, monosomy rescue, post-fertilisation errors, and gamete complementation. Problems associated with UPD include trisomy mosaicism, genomic imprinting, homozygosity of autosomal recessive mutations, or even a combination of these. Supernumerary marker chromos...