All People With Blue Eyes Have A Single, Common Ancestor

Calendar October 10, 2022 | Posted by admin

According to the Cleveland Clinic, up until some 10,000 years ago, it’s believed everyone in the world had brown eyes. Now, an estimated 8-10% of people in the world have blue eyes. How did that come to be? As it turns out, researchers now believe blue eyes all started with a single person who passed on a genetic mutation that spread across the world. In other words, everyone with blue eyes shares a single, common ancestor.

Back in 2008, researchers with the University of Copenhagen examined the exact genetic mutation that resulted in blue eyes all those years ago. Their research was published in the The Journal of Human Genetics. According to Science Daily, the study’s lead author, Professor Hans Eiberg, explained that humans originally had brown eyes, and a gene mutation “turned off” the ability to produce brown eyes – resulting in some people having blue eyes. The press release elaborated that the affected gene, the OCA2 gene, regulates brown pigment in the eyes. If the OCA2 gene had been completely destroyed or “turned off” then the affected humans would be without any melanin in their hair, eyes, or skin color (a condition known as albinism). But with the specific mutation, the body has a limited ability to produce melanin in the iris, resulting in a blue iris, rather than a brown iris. The genetic mutation isn’t a positive or negative trait.

“Mutations can affect things like freckles, balding patterns, hair color, and more“. “It simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so,” explained Eiberg.

According to the College of Physicians of Philadelphia, researchers studied the mitochondrial DNA of individuals with blue eyes from various countries, such as Jordan, Denmark, and Turkey. The researchers found that over 97% of the blue-eyed people in the study shared a single haplotype – a grouping of genomic variants that are usually inherited. Because of this, researchers believe that the mutation is passed on genetically, meaning that everyone with blue eyes is related.

“From this, we can conclude that all blue-eyed individuals are linked to the same ancestor. They inherited the same switch at the same spot in their DNA,” said Eidberg in a press release, shared in EurekaAlerta!,

Source: https://blog.thebreastcancersite.greatergood.com

Category Categories: Uncategorized  |  Tag Tags: , , , , , , , , , , , , , , , ,

New DNA-based Strategy To Fight Aggressive Cancers

Calendar March 6, 2020 | Posted by admin

Researchers from the University of Copenhagen have discovered that our cells replicate their DNA much more loosely than previously thought. The new knowledge might be useful for developing novel treatments against aggressive forms of cancers. This was found by inhibiting the essential gene DNA polymerase alpha, or POLA1, which initiates DNA replication during cell division. The discovery gives researchers new insights into DNA replication and may potentially be used for a new type of cancer treatment.

‘If we are visionaries, I would say that we might be at the birth of a whole new set of molecules that could be used in fighting cancer’, states  Research Leader and Associate Professor Luis Toledo of the Center for Chromosome Stability at the Department of Cellular and Molecular Medicine. ‘Basically, if we turn the finding on its head, this novel strategy aims at exploiting an in-built weakness in cancer cells and make them crash while they divide.’

When a cell divides, the double DNA strand is opened lengthwise like a zipper that is unzipped. The new double strands are built at each of the separated strands, so that you gradually end up with two new “zippers”.

Before the new halfs of the zipper are made, a bit of DNA is temporally exposed in single stranded form. This process is required for the new zippers to form. Nevertheless, large amounts of single-stranded DNA have traditionally been considered by researchers to be a sign of pathological stress during cell proliferation. However, the researchers behind the new study discovered that DNA unzippers act more loosely than expected. This can generate large amounts of single-stranded DNA, which the researchers now show is no more than a form of natural stress that cells can actually tolerate in high quantities. Still, for this tolerance to exist, cells require a sufficient amount of the protective protein RPA to cover the single-stranded DNA parts.

’We have seen that cells can duplicate their genome, even with large amounts of single stranded DNA. They can divide and go on living healthily because they have a large excess of RPA molecules that acts as a protective umbrella.’ says the study’s first author and former postdoc at the University of Copenhagen Amaia Ercilla, adding: ‘But there is a flip side of the coin. When we make the cells generate single strand DNA faster than what they can protect, chromosomes literally shatter in hundreds of pieces, a phenomenon we call replication catastrophe. We always thought that we could use this for instance to kill cancer cells“.

Source: https://news.ku.dk/

Category Categories: Uncategorized  |  Tag Tags: , , , , , , , , , ,