Chromosome

Discoveries about the end-replication problem indicate both telomerase and the CST–Polα-primase complex are essential for chromosome protection, suggesting a revision in the science of telomeres and potential impacts on genetic disorders. Credit: SciTechDaily.comRecent research challenges the long-standing understanding of the end-replication problem in DNA, revealing two distinct issues rather than one.Half a century ago, scientists Jim Watson and Alexey Olovnikov independently realized that there was a problem with how…

The sex of human and other mammal babies is decided by a male-determining gene on the Y chromosome. But the human Y chromosome is degenerating and may disappear in a few million years, leading to our extinction unless we evolve a new sex gene.The good news is two branches of rodents have already lost their Y chromosome and have lived to tell the tale.A recent paper in Proceedings of the National Academy of Science shows how the spiny rat has evolved a new male-determining gene.How the Y chromosome determines human sexIn…

The immune system is meant to protect us from alien invaders like bacteria and parasites, and zombie-like takeovers by viruses and cancerous mutations. As grateful as we are for this protective system, for some it can get a little overzealous, becoming so hypervigilant it attacks its own body's tissues. With conditions like type 1 diabetes, rheumatoid arthritis, lupus, and multiple sclerosis in its ranks, autoimmune disease is third most prevalent disease category, outstripped only by cancer and heart disease.Such immune…

Cancerous bladder cells with a missing Y chromosome are better prepared to evade our immune system, according to a new study using mice and conducted by researchers from Cedars-Sinai Medical Center and The Ohio State University in the US.The discovery goes some way to explaining why so many cases of specific cancers contain cells that no longer have a male sex chromosome and potentially why men are statistically more prone to cancer.Like hair color, skin elasticity, memory, and eyesight, the Y chromosome has a habit of…

The sex of human and other mammal babies is decided by a male-determining gene on the Y chromosome. But the human Y chromosome is degenerating and may disappear in a few million years, leading to our extinction unless we evolve a new sex gene.The good news is two branches of rodents have already lost their Y chromosome and have lived to tell the tale.A recent paper in Proceedings of the National Academy of Science shows how the spiny rat has evolved a new male-determining gene.How the Y chromosome determines human sexIn…

Supernumerary sex chromosome aneuploidy refers to a condition in which individuals have an extra sex chromosome, resulting in an abnormal number of chromosomes in their cells. This condition can occur when there is an error in the division of chromosomes during cell division, leading to an unequal distribution of chromosomes in the resulting cells.A Geisinger study has uncovered that individuals with supernumerary sex chromosome aneuploidy, a condition characterized by an extra X or Y chromosome, are at a heightened risk…

The sex of human and other mammal babies is decided by a male-determining gene on the Y chromosome. But the human Y chromosome is degenerating and may disappear in a few million years, leading to our extinction unless we evolve a new sex gene.The good news is two branches of rodents have already lost their Y chromosome and have lived to tell the tale.A new paper in Proceedings of the National Academy of Science shows how the spiny rat has evolved a new male-determining gene.How the Y chromosome determines human sexIn…

Katie and her husband, Simon, had never heard of XXY, and their obstetrician wasn’t much help either. Also known as Klinefelter syndrome, XXY is a genetic condition that can cause infertility and other health issues; it occurs when a child, typically assigned male at birth, is born with an extra X chromosome in addition to the usual X and Y.  Sex chromosome variations, in which people have a surplus or missing X or Y, are the most common chromosomal conditions, occurring in as many as one in 400 births. Yet the majority…

Scientists experimenting on mice have found evidence that key parts of the modern human brain take more time to develop than those of our long extinct cousin, the Neanderthal.Like the hare and the tortoise, slow and steady is the winner here. The extra time is caused by protein differences that also appear to reduce chromosome errors, ultimately resulting in a healthier, more robust population.  The study's results imply that this step in the development of our neocortex (the wrinkled outer layer responsible for higher…

Just because a human egg is fertilized does not mean the embryo will survive to birth. In the first few weeks of conception, there's a whole lot that can still go wrong.When a fertilized egg first begins to divide, it must duplicate its entire genome – that's all the DNA instructions stored in the cell – so that each of the two resulting cells can receive an exact copy. This process must be immaculately repeated each time a cell divides.   But sometimes, it can miss a chromosome or make an extra copy of one.Scientists…