Last Week in Science (19th Nov 2023)


Penguins and Their Black Dots

Chirping and singing sparrows
Mark each other with their sounds
But penguins use their dots to find their marrows

Humans and other primates can recognize individuals of their species. But are there other organisms that can identify other members of their species. Many organisms ranging from whales to wasps are known to do so. While birds use sound to identify other birds, it is seen that other organisms can also visually recognize each other. So, how does this visual recognition occurs? We find an answer for one organism, which is African penguins. These penguins have black dots on their chest that is covered in white feathers and each penguin has a unique pattern of dots.

The workers of a zoo in Italy use this pattern to identify individual penguins. Researchers at the University of Turin, Italy used the animals that were housed at this zoo to see whether  the penguins themselves use the same pattern for identification. They performed some interesting experiments, where a penguin was shown photos of their mate and another penguin. The penguin could easily recognize their mate's photo as it stared at it for long. Now, when the black dots were digitally removed from the photos, the penguin failed to identify its mate. 

The beauty of these findings is how both humans and penguins identify penguins using the same black dots. It would be interesting to see if other birds and animals can also identify individuals of other species.

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The Cooperative Bonobos

Together we walk, hand in hand
Taking the humanity ahead
Is that something which the bonobos planned?

Identification of individuals within a group of a specific species is necessary for cooperation amongst individuals of a group. Why do individuals need to cooperate? The reason is similar to why humans need to cooperate, i.e. for food, shelter and reproduction. But we do not know how and when this cooperative behaviour evolved. 

To answer this question, another interesting question was posed by the researchers at Harvard University, Max Planck institute, Leipzig and German Primate Center, Gottingen - whether bonobos, primates that are much more closely related to humans than Chimpanzees, can cooperate with individuals of different groups. They found that yes, bonobos indeed can cooperate outside their groups. This cooperation was seen for food sharing and grooming. They also saw that the individuals that cooperated more within their own groups (equivalent of human families), cooperated more with other groups also. It was interesting to see that this was something that was not rare and wasn't being used for any personal benefit of a bonobo. Do we humans have something more to learn from bonobos that our ancestors missed?  

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Breakthrough gene therapy approved in UK

Red blood cells (RBCs) are one of the major components of blood. They contain haemoglobin that helps in transporting oxygen, which is required by all the cells of the body. What will happen if this hemoglobin (Hb) is not formed properly? Anemia, which can also happen due to dietary deficiency occurs in that case. But unlike anemia in which dietary supplements can help, here they do not help and requires blood transfusion.

The instructions to form hemoglobin is present in our DNA. At times, one or more of the letters of DNA coding for Hb changes and that causes the cell to form defective Hb. In a disease called as Sickle Cell Anemia, because of the presence of defective Hb the RBCs change their shape and become like a sickle in shape, as molecules of Hb clump together. The sickle shaped RBCs cannot pass from narrow blood vessels and capillaries thus leading to blockage. The blockage causes pain in whichever body part doesn't receive blood and therefore oxygen due to blockage. There is another disease where regular blood transfusions are needed, known as thalassemia. In this disease also Hb does not form because of a defect in the DNA that codes for Hb. Individuals with Sickle Cell or Thalassemia suffer pain and emergency hospital visits frequently. 

Many researchers have been trying to cure the disease by correcting the instruction code i.e., the defective DNA present in the patients that codes for Hb. Recent advances in editing DNA uses a breakthrough technology known as CRISPR-Cas (that won the 2020 Nobel Prize in medicine) has make this correction of DNA possible. 

Now a recent clinical trial has shown that patients who were given gene therapy known as Casgevy did not require any blood transfusion or faced painful episodes for over a year. Looking at these promising rules UK has approved gene therapy as a treatment for Sickle Cell Anemia and a type of Thalassemia known as β-thalassemia. Although, the current gene therapy is expensive but we do hope that new and inexpensive gene therapy is on its way for patients who have been suffering from such debilitating genetic diseases where the change in DNA that causes the diseases is known.