人類遺伝学と発生学

Ring chromosome is a disorder in which one or both ends of chromosome are lost and joined, so they could show a ring-shaped structure. Patients with ring chromosome could therefore present with features of deletion of long or short arms of the chromosome syndromes or a combination of both. Phenotypic of these individuals depends on the size of the ring chromosome, amount of genetic material lost in breakage, the stability of the ring chromosome and the presence of secondary chromosomal aberrations including the varying degrees of mosaicism. Ring chromosomes accounts for a very low percentage of structural chromosomal abnormalities but could lead to a major clinical concern and complicated genetic counseling. Practitioner awareness must be permanently raised up to help in managing with efficacy patient with ring condition. We report here 4 cases of ring on chromosome 4, 9, 15 and X. We described their clinical finding and draw attention on common key signs that were present in the reported cases and also discussed recurrence risk.

The objectives of this study were to examine the prevalence and to characterize the types of chromosomal aberrations of aneuploidy in cleavage-stage Day 3 human embryos and in Day 5/6 human blastocysts in indigenous Black African women aged ≤ 35 and >35 years. Of the 312 oocytes fertilized for Day 3 embryos and 269 for Day 5/6 blastocysts, 230 blastomeres and 122 blastocysts were biopsied respectively and then subjected to genetic analysis using the array CGH and next generation sequencing methods, genotyping to characterize chromosomal error types of aneuploidy across all 24 chromosomes. A total of 562 oocytes with 486 MII oocytes, were fertilized from which 230 Day 3 embryos and 122 Day 5/6 blastocysts were biopsied. Euploidy rates in Day 3 embryo group and in Day 5/6 blastocyst group were 24.3% and 75.0% respectively while aneuploidy rates were 75.7% and 25.0% respectively. Women aged ≤ 35 years were approximately thrice as likely to have euploid Day 3 embryos (Fisher’s χ²=1.18, p-value=0.29, OR=2.79, 95% CI: 0.61, 12.67). Blastocyst stage biopsy was more efficient in PGS. Blastocyst culture had some level of aneuploidy selection. Higher diagnosis rate was observed as there was lower rate of embryos with no diagnosis.

The study of DNA extraction from bones is an important part of archaeogenetics. This study has provided a new investigating power to view and understand the human past. Gandhara Graves are widespread throughout the Gandhara region, from Bajaur to the Indus in Pakistan. The graves are not only widespread throughout Gandhara but other regions (the areas east-of the Indus River) as well. Dani has divided Gandhara Graves into three distinct groups belong to three distinct periods. In the present article, the systematic research has been undertaking by the researchers to isolate DNA from the fragments of human skeletal remains recovered from Gandhara graves. Although in this regards the researchers have mentioned novel methods that could be used for DNA extraction but the only method applied is ethanol/chloroform precipitation-based PCR amplifiable method for DNA Extraction from the human skeletal remains recovered from Gandhara grave sites.