Loss of heterozygosity through inbreeding or mitotic errors leads to reductions in progeny survival and fertility. Loss of heterozygosity is particularly exacerbated in geographically isolated populations, which are prone to inbreeding depression and faster rates of extinction. The regenerative capacities of the hermaphroditic biotype of the planarian Schmidtea mediterranea allowed us to perform a systematic genetic test of Mendelian segregation and study the loss of heterozygosity in the Spiralian superclade in general and planarians in particular. We discovered that ~300 Mb (~37.5%) of the genome retains heterozygosity even after ten generations of inbreeding, and show that these chromosomal regions have low diversity and recombination rates in wild populations. Our genetic and genomic analyses establish S. mediterranea as a genetically tractable system. The research also opens the door to study the evolutionary basis of non-Mendelian mechanisms, the adaptive advantages of chromosome structural heterozygotes and their potential relationship to the robust regenerative capacities of planarians.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5556695 | PMC |
http://dx.doi.org/10.1038/s41559-016-0019 | DOI Listing |
Genes Chromosomes Cancer
January 2025
Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, presenting with heterogeneous clinical and molecular subtypes. While gene fusions are predominantly associated with alveolar RMS, spindle cell RMS, especially congenital and intraosseous variants, are also linked to specific gene fusions. Furthermore, recently, FGFR1 kinase-driven RMSs were published.
View Article and Find Full Text PDFInt J Gynecol Pathol
January 2025
Diagnostic Pathology, National Cancer Center Hospital.
Vulvar adenocarcinoma of the intestinal type (VAIt) is a rare subtype of primary vulvar carcinoma, with ∼30 cases documented in the English literature. This study presents 2 new cases of HPV-independent VAIt with lymph node metastasis and discusses their clinical presentation, histopathologic features, and whole exome sequencing (WES) analysis. Both cases exhibited histologic features consistent with VAIt, including tubular, papillary, and mucinous carcinoma components.
View Article and Find Full Text PDFJ Hematop
January 2025
Mayo Clinic, Rochester, MN, USA.
Testicular follicular lymphoma (TFL) is an exceedingly rare lymphoma that typically occurs in young male patients and is now recognized as a distinct diagnostic entity in the International Consensus Classification. TFL shows some clinicopathologic and genetic overlap with pediatric-type follicular lymphoma (PTFL). We report a case of TFL occurring in an otherwise healthy 4-year-old boy who presented with painless scrotal swelling.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Department of Women's and Children's Health, University of Padova, 35128 Padova, Italy.
Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder that causes a range of developmental problems including cognitive and behavioral impairment and learning disabilities. FXS is caused by full mutations (FM) of the gene expansions to over 200 repeats, with hypermethylation of the cytosine-guanine-guanine (CGG) tandem repeated region in its promoter, resulting in transcriptional silencing and loss of gene function. Female carriers of FM are typically less impaired than males.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!