Posted in Science & Nature


In February 1951, a woman named Henrietta Lacks was diagnosed with cervical cancer. The cancer was aggressive and her health quickly deteriorated, until her ultimate demise in October 1951. Although Henrietta Lacks passed away on that day, not all of her was dead. A scientist named George Otto Gey succeeded in culturing (growing on a petri dish) the biopsied cervical cancer cells, provided by Lacks’ physician. He discovered that this lineage of cells could keep dividing and growing without stopping. In the human body, cells will eventually reach a limit of dividing and be destroyed. The cells from Henrietta Lacks, however, were immortal. Gey named this cell line HeLa, taking the first two letters of Lacks’ first and last names.

The HeLa cell line (and all other immortal cell lines since) have proven very useful in research as they give an infinite supply of identical cells, giving scientists a model template they can experiment on. The immortality of the HeLa cells is such that 60 years later, scientists are still using cells from that lineage – cells virtually identical to the cells taken from Henrietta Lacks (save for random mutations that happen in any cells). The cells are so well-adapted to unlimited growth that they are sometimes considered a laboratory “weed”, because it can easily invade another cell culture and completely take it over. One biologist even went as far as claiming that HeLa cells were no longer human, but instead a new species. He supported his claim with the fact that HeLa cells are self-sufficient and can reproduce on its own, and that it has a different genome (even chromosome numbers) to human cells due to the nature of cervical cancer.

The main issue with HeLa cells is the ethics behind it. At no point did Lacks or her family give permission to the doctor for him to donate her cells for research. Since her death, the cells were not only used for the purpose of pure research, but also commercialised. Unfortunately, medical ethics was not well-established at the time and asking the patient’s consent for such things was not common. The two major sides in this debate would be the unethical act of taking human tissue and using it without consent, versus the potential benefit it brings. For example, HeLa cells were used by Jonas Salk for his research that led to the development of the polio vaccine. It may be a stretch, but if those cells were not taken from Lacks, the development of the polio vaccine may have been delayed and countless more people would have suffered from a lifelong crippling illness. This is the great question in medical ethics: how much of an individual’s human rights can we afford to sacrifice for the needs of the many? Do the needs of the many really outweigh the needs of the few, or the one?

Posted in Psychology & Medicine


They say that human imagination is infinite and limitless. But consider this: can you imagine a colour outside of the visible spectrum? Most likely, you are incapable of thinking of a new colour that cannot be mapped on a standard colour chart. Interestingly, a small proportion of people can see and understand colours beyond the range that the majority of us can see.

The physiology of vision is rather complex, but essentially boils down to the retina (inside lining of the eyeball) acting as a film for the image that you see. Cells known as photoreceptors convert the visual image into electrical signals that are transmitted to the occipital lobe of the brain via the optic nerve. There are two types of photoreceptors: rod cells, which sense movement, and cone cells, which sense colour and provide sharp images (visual acuity). Human beings typically see colour by combining three primary colours: red, green and blue (known as the RGB system). There are cone cells for each primary colour. The brain processes the signals sent by each cone cells and figures out what “colour” you are seeing. Therefore, you can only perceive colours made from a combination of red, green and blue. It is easy to visualise this by playing with colour palettes on computer programs such as Photoshop.

In recent years, it has been speculated that a certain percentage of women have an extra type of cone cell that senses a different wavelength of light. Ergo, they can theoretically sense a greater range of colours compared to someone who has three types of cone cells. This condition is called tetrachromacy (“four colours”). Tetrachromacy is the opposite to colour blindness, which is caused by a deficiency or fault in one or two types of cone cells. To these people, the average person (a trichromat) will appear “colour blind”.

According to one estimate, as many as 12% of women are tetrachromats. Although there are many theoretical barriers to true tetrachromacy, there have been several documented cases of women who perceive colour in much more depth.

The ability to see an extra primary colour is more significant than just a 25% increase in the person’s colour range. An average person can see about 1 million different hues (shades of colours), while a true tetrachromat can see 100 million hues – a hundred-fold increase in the range of colours they can see. One can only wonder what kind of amazing sights a tetrachromat sees when she gazes upon a field of flowers or even a rainbow. Unfortunately, even if a tetrachromat tried to explain the colours she saw to us, we would not be able to grasp the colours as our minds would be incapable of visualising the colours, much like how describing the colour red to a blind person is impossible.