In all, 11 to 16 copies of this DNA are spotted for each gene to be placed on the array. Oligonucleotide arrays (trademarked as a GeneChip by Affymetrix) use small 25 base pair gene fragments as the DNA to be spotted onto an array. Two main types of commercial microarrays, oligonucleotide arrays (Affymetrix) and cDNA arrays (BD Biosciences and others), provide good examples of how this technology works. By exposing the microarray to a fluorescently labeled sample the DNA that hybridizes will be identifiable as glowing spots on the array, while the spots that have nothing hybridized to them will not be visible. DNA or RNA in the overlaid sample will stick (through a process called hybridization) to a complementary spot on the array, that is, Gene-A will stick to a spot composed of a Gene-A fragment. The main advantage of microarrays is that the spots are single stranded DNA fragments that are strongly attached to the slide, allowing cellular DNA or RNA to be fluorescently labeled and laid overtop of the array. Through the use of highly accurate robotic spotters, over 30,000 spots can be placed on one slide, allowing molecular biologists to analyze virtually every gene present in a genome. Each DNA fragment representing a gene is assigned a specific location on the array, usually a glass slide, and then microscopically spotted (less than 1 mm) to that location. This high throughput method allows for the global study of changes in gene expression, giving us a complete cellular snapshot.Ī DNA microarray consists of an orderly arrangement of DNA fragments representing the genes of an organism. Enter the microarray: a technological advancement that within the last 7 or 8 years has allowed scientists to study many, if not all, the genes of an organism’s at once. For many years, study of a gene in this manner had to be done individually-looking at whether a specific gene is turned on (upregulated) or turned off (downregulated) under certain conditions1. The production of mRNA is very much a reflection of the activity level of a gene, and a lot of genetic information can be understood by studying it. At any rate, the mechanism by which genes are utilized is the same for all cells and involves the transcription of a gene into mRNA before being translated into a protein. This is idea is easy to digest when you think about how a single-celled embryo goes on to produce all kinds of different tissues. These authors contributed equally to this work.SPOT YOUR GENES – AN OVERVIEW OF THE MICROARRAYĪ cell functions by using its genes to produce proteins and although each cell within an organism will usually contain the same set of genes, there are significant differences in which genes are activated and how they are controlled. Our results showed that WGS could provide a more comprehensive detection of genetic variations in fetuses with structural abnormalities in a simpler procedure. Using WGS, we detected not only aneuploidies and copy number variations (CNVs), but also single nucleotide variations (SNVs)/insertions and deletions (indels), trinucleotide repeat expansion, and exonic CNVs with high accuracy in an acceptable turnaround time (3-4 weeks). To evaluate the accuracy, efficacy, and incremental yield of whole genome sequencing (WGS) compared with chromosomal microarray analysis (CMA) for routine prenatal diagnosis.Ĭompared with CMA, WGS increased the additional detection rate by 5.9% (11/185) in 185 fetuses with structural anomalies. WGS is a promising prenatal diagnosis method that can identify aneuploidies, CNVs, SNVs/indels, TREs, and exonic CNVs in fetuses with structural anomalies. Patient consent: Informed consent was obtained from all the study participants at the time of providing samples. and 82103927 to M.H.), the Natural Science Found of Jiangsu province (BK20210037 to M.H.) the Maternal and Children Health Project of Jiangsu Province (F202158 to F.Q.) and the Scientific Research Project of Jiangsu Maternal and Children Health Care Association (FYX202118 to F.Q.).ĭate sharing: All the data generated or analyzed in this study are included in this published article.Įthical approval: The research Ethics Committee of Nanjing Maternity and Child Health Care Hospital approved the study (KY-080) in accordance with the Helsinki Declaration of 1975, as revised in 2000. and 2021YFC1005301 to P.H.), the National Natural Science Foundation of China (No. This work was supported by the National Key R&D Program of China (2022YFC2703400 to Z.X. Conflicts of interests: The authors declare that they have no conflict of interest.
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