Category Biology

What is Genetically Modified Organism?

You must have often read about genetically modified organism (GMO) in newspapers. Let us know about it.

What is GMO?

GMO is an animal, plant, or microbe whose DNA has been altered using genetic engineering techniques. Genetically modified animals are mainly used for research purposes, while genetically modified plants are common in today’s food supply.

The specific targeted modification of DNA using biotechnology has allowed scientists to improve the genetic makeup of an organism without unwanted characteristics.

History

For thousands of years, people have been using breeding methods to modify organisms. Corn, cattle, and even dogs have been selectively bred to have certain desired traits.

The conventional methods- selective breeding and crossbreeding-can take a long time. Meanwhile, these methods often produce mixed results, with unwanted traits appearing alongside desired characteristics.

In last few decades, modern advances in biotechnology have allowed scientists to directly modify the DNA of microorganisms, crops, and animals. Genetically modified foods were first approved for human consumption in the U.S. in 1994.

Present day

GMOS produced through genetic technology have become a part of everyday life, entering society through agriculture, medicine, research, and environmental management.

Today, approximately 90% of the corn, soybeans, and sugar beets in the market are GMOS.

Pros and cons

While GMOs have been a benefit to human society in many ways, the production of GMOs remains a highly controversial topic in many parts of the world.

Genetically engineered crop produce higher yields, have a longer shelf life, are resistant to diseases and pests, and even taste better. These benefits are plus for both farmers and consumers.

However, genetic engineering raises the possible risk of unexpected allergic reactions to some GMO foods.

Also, genetic engineering changes an organism in a way that would not occur naturally scientists insert genes into an organism from an entirely different organism.

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What is ‘domestication syndrome’?

Thousands of years ago all species of animals lived in the wild and roamed our planet freely. However, centuries ago, humans domesticated some species for their own benefit. This list is fairly endless from dogs, donkeys, camels, and horses to cattle, sheep, pigs, and goats. In the 19th Century, naturalist Charles Darwin was among the earliest to detect something interesting about these animals "different species often developed similar changes when compared to their ancient wild ancestors”. How could that be? Come, let's find out.

The set of shared changes seen in domesticated animals is referred to as "domestication syndrome". And, for long, one of the main reasons for this was attributed to the tamer behaviour of domesticated animals. It is understandable that our ancestors would have selected calmer animals of the lot for domestication, and so, this trait continued in the subsequent generations too, irrespective of the species. Some of the noticeable changes are "shorter faces, smaller teeth, more fragile skeletons, smaller brains, and different colours in skin, fur, and feathers". (Remember, not all species display all the changes. A few species may share several of these changes while some may share just a few. But all of them seem to display at least a few changes.)

One of the theories associated with tamer behaviour is that it "somehow triggered all of the other traits too". Another theory states that "selection for tameness causes the other features because they're all linked by genes controlling neural crest cells. These cells, found in embryos, form many animal features-so changing them could cause several differences at once". However, a new hypothesis by researchers suggests that these theories are over-simplified and do not offer the complete picture. They say the "removal of pre-existing selection" is as important as tameness. For instance, domesticated animals may not face the threat of predators, and "so wild traits for avoiding them might be lost. Similarly, competition for mating partners too comes down, bringing down "wild reproductive features and behaviours". Since domesticated animals are provided food, this could change not just their "metabolism and growth" but even their features over a period of time.

The researchers argue that several selective changes are at play when it comes to the characteristics of domesticated animals, not just "selection for tameness".

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Where the World’s largest bacterium discovered?

Scientists have discovered the world’s largest-known bacterium, in the form of white filaments the size of human eyelashes, on the surfaces of decaying mangrove leaves in a swamp in Guadeloupe in the Caribbean Sea.

Around 1 cm long, Thiomargarita magnifica is 50 times larger than all other known giant bacteria and the first to be visible with the naked eye. Researchers have compared it to a human encountering another human as tall as Mount Everest.

In most bacteria, the genetic material floats around freely inside the cell. T. magnifica keeps its genetic material inside membrane- bound compartments throughout the cell. It was also found to contain three times as many genes as most bacteria.

The discovery suggests that “large and more complex bacteria may be hiding in plain sight”.

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Why are some people mosquito magnets?

Are you someone who gets bitten by a lot of mosquitoes, even when those around you aren’t complaining much about it? Researchers from the Rockefeller University in New York have made some headway in the question of why some people are mosquito magnets. They have demonstrated through a study as to why certain people attract more of a species of these insects than others.

Round-robin tournament!

In their results published in Cell in October 2022, the researchers talk about their three-year study that helped them to their conclusions. Participants were asked to wear nylon stockings over forearms for six hours each day. After repeating the process over multiple days, the researchers tested the nylons over the next few years in a round-robin style tournament.

Using a chamber of their own design, the nylon stockings were paired against each other in all possible manners. As the chamber was divided into two tubes and each of these ended in a box that had a stocking, the researchers were able to observe as the Aedes aegypti mosquitoes flew towards one nylon stocking rather than the other, once they were introduced in the main chamber.

By the end of their study, researchers were able to see that one particular sample proved to be a compelling target for the mosquitoes. While this sample was four times more attractive to the mosquitoes than the second-most attractive sample, it was 100 times more attractive than the sample that proved to be least attractive to mosquitoes.

Mosquitoes track the scent

After sorting the samples into high and low attractors, the researchers resolved to find out what differentiated them. They discovered that people who are mosquito magnets produce carboxylic at a much higher level. These substances are in the moisturising barrier on the skin, called sebum, which helps form a protective coating on our skin and are also used by bacteria on our skin to produce our unique human odour.

By enrolling more people for a validation study, the team involved in this research were able to confirm their findings. While these are still early days, it opens up the potential of manipulating our skin biomes in order to be less attractive to mosquitoes. For now, the researchers are hoping that their paper will inspire researchers to test other mosquito species and find out whether this is universal to mosquitoes or specific to the Aedes aegypti species.

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WHO COINED THE TERM GENETICS?

William Bateson was an English biologist who was the first person to use the term genetics to describe the study of heredity, and the chief populariser of the ideas of Gregor Mendel following their rediscovery in 1900 by Hugo de Vries and Carl Correns. His 1894 book Materials for the Study of Variation was one of the earliest formulations of the new approach to genetics.

Bateson became the chief popularizer of the ideas of Mendel following their rediscovery. In 1909 he published a much-expanded version of his 1902 textbook entitled Mendel’s Principles of Heredity. This book, which underwent several printings, was the primary means by which Mendel’s work became widely known to readers of English.

“Bateson first suggested using the word “genetics” (from the Greek [Offsite Link]  genn?, ?????; “to give birth”) to describe the study of inheritance and the science of variation in a personal letter to Alan Sedgwick… dated April 18, 1905. Bateson first used the term genetics publicly at the Third International Conference on Plant Hybridization in London in 1906. This was three years before Wilhelm Johannsen used the word “” to describe the units of hereditary information. De Vries had introduced the word “pangene” for the same concept already in 1889, and etymologically the word genetics has parallels with Darwin’s concept of pangenesis.

Bateson co-discovered genetic linkage with Reginald Punnett, and he and Punnett founded the Journal of Genetics in 1910. Bateson also coined the term “epistasis” to describe the genetic interaction of two independent traits.

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WHAT IS BIOLOGICAL WEATHERING?

When lichen and moss growing on a rock create an environment that causes rocks to break down both physically and chemically.

Biological weathering also means organic weathering. It is the disintegration of rocks as a result of the action by living organisms. Plant and animals have a significant effect on the rocks as they penetrate or burrow into the soil respectively. Biological weathering can work hand in hand with physical weathering by weakening rock or exposing it to the forces of physical or chemical weathering.

For instance, some plants and trees grow within the fractures in the rock formation. As they penetrate into the soil, and their roots get bigger, they exert pressure on rocks and make the cracks wider and deeper that weaken and eventually disintegrate the rocks. Microscopic organisms can also produce organic chemicals that can contribute to the rock’s mineral weathering.

Biological weathering is a very common type of weathering that we see around us. There are many small animals that bore hole in the rock and live inside it. Over the time, they burrow and widen cracks and end up breaking rocks apart. Then there are bacteria, algae and lichens produce chemicals that help break down the rock on which they survive, so they can get the nutrients they need. They produce weak acids which convert some of the minerals to clay. We, humans, are also responsible for biological weathering. As we construct more homes, industries, dams, power plants, roads, we rip the rocks apart.

Credit: Earth Eclipse

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