Sickle Cell Anemia

Sickle cell anemia is a genetic disease prevalent in human populations in Africa and other warmer regions of the world. A mutated allele of a gene coding for β - globin subunit of hemoglobin, the oxygen carrying pigment, causes an abnormality of the hemoglobin molecules. The presence of this abnormal hemoglobin in red blood cells changes the shape of the RBCs to curve as a sickle from its disk-shape. Individuals with this disorder have fewer numbers of RBCs, and hence develop anemia. This is because the sickled RBCs breakdown prematurely. The mutation substitutes glutamic acid at a particular place in the primary structure of the β-globin with valine which results in abnormal folding of hemoglobin. The mutated allele is codominant, which means both normal β globin and mutated β globin are produced in individuals who are the heterozygous for this locus. Therefore, they have both good and bad hemoglobin and hence both normal and sickled RBCs are present. They are normally healthy and are the carriers of the mutant allele. Since the mutated alleles cause severely detrimental effects in homozygous individuals, normally they should have been eliminated from the human population by natural selection. However, there is prevalence of malaria in warmer countries like in Africa; the heterozygous individuals will survive malaria attacks better than individuals with homozygous wild type alleles. This is because, the malaria parasite cannot survive in sickled RBCs. Therefore, at heterozygous individuals, parasite density remains at a lower level.

Comments

DAMA/LIBRA: The Dark Matter Signal No One Else Can See

DAMA/LIBRA: The Dark Matter Signal No One Else Can See Dark matter is one of the universe's biggest mysteries. We can’t see it, touch it, or measure it directly — but without it, galaxies wouldn’t hold together. Physicists around the world are racing to detect this elusive substance. And one experiment buried deep beneath Italy’s Apennine Mountains says it already has. For over two decades, the DAMA/LIBRA experiment has reported a consistent signal that it claims could be the first direct evidence of dark matter. The problem? No one else can see it. The Invisible Majority Let’s rewind for a moment. Everything we can see—planets, stars, gas, and dust—makes up less than 5% of the universe. About 27% is thought to be dark matter , an invisible substance that doesn't emit or reflect light but exerts a powerful gravitational pull. It's what keeps galaxies spinning faster than gravity from visible matter alone can explain. But detecting dark matter is no easy task. If it’s...

De-Extinction Dreams: Bringing Back Mammoths, or a Pandora’s Box?

There was a time when bringing extinct creatures back to life was just the stuff of novels and movies. Now, it’s not so far-fetched. Scientists are serious about the idea — especially when it comes to woolly mammoths. The basic idea? Use preserved DNA and modern genetic tools to engineer something close to what used to roam the Earth thousands of years ago. That "something" might not be a true mammoth — not genetically, anyway — but more of a cold-adapted elephant with mammoth-like traits. Some believe these creatures could help restore damaged ecosystems in the Arctic. Others wonder if we’re simply crossing a line we can’t uncross. Either way, this is no longer science fiction. The Mammoth Plan Woolly mammoths went extinct a few thousand years ago, leaving behind frozen remains in the tundra — some with hair, skin, even bits of usable DNA. That’s more than enough to get geneticists interested. One of the more vocal efforts comes from Colossal Biosciences, a company aim...

Myth Busted: Sitting Close to the TV Won't Make You Go Blind

Myth Busted: Sitting Close to the TV Won't Make You Go Blind We've all heard the age-old admonishment from parents and grandparents: "Don't sit too close to the TV; it'll ruin your eyes!" It's one of those timeless warnings that have been passed down through generations. But is there any truth to this claim? Does sitting close to the TV screen really pose a risk of going blind? In this article, we'll dive into the science behind this common belief and debunk the myth once and for all. The idea that sitting too close to the TV can damage your eyes likely stems from a time when cathode ray tube (CRT) TVs were the norm. These older TVs emitted low levels of radiation, and there were concerns about potential harm. However, modern TVs, such as LED and LCD screens, operate differently and don't emit harmful radiation. Before we debunk the myth, let's understand how our eyes function. When you focus on an object, whether it's a TV screen or a bo...

Science & I

Search This Blog