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You must have heard about genes, DNA, chromosomes, and inheritance in your genetics class. But have you really understood it? The subject can be difficult for many, but it has some cool, fun facts related to your life.
Read on as we learn more about the mysteries of your genes.
Genes are the basic unit of inheritance. They are like instructions written on DNA that tell cells what to do and are lined up on chromosomes in the center of cells. These instructions guide cells on how to perform certain tasks, which in turn determine the physical characteristics of a human being like hair color eye color, or height.
Nearly every cell in our bodies carries a copy of chromosomes, usually tucked away in a special compartment called the nucleus. Chromosomes are long strands of a chemical called DNA.
So, what is DNA? Imagine DNA as a twisted ladder, with genes arranged like letters on each rung. These genes act as an instruction manual. Each gene's sequence of letters holds details on how to create specific molecules, like proteins or hormones, which are vital for our body's growth and development.
Even though every cell has two copies of each gene, it only needs certain ones turned on to do its job. The rest stay inactive.
Sometimes, a gene can have a change that messes up its instructions. This change might happen out of the blue or be passed down through families. These changes are called mutations, and they result in a number of different diseases.
Now that you have the foundational knowledge of genes let’s have a look at some of the interesting facts about them that you need to know.
Humans share a lot more similarities than we might think. Actually, over 99.9% of our genes are identical to every other human being. This means that the physical or functional differences we notice, like eye color, height, intelligence, or other traits, come from less than 0.1% of our genetic makeup. These variations are what make each of us unique.
Humans and chimpanzees share similarities but also have key differences, especially in brain function. Despite outward distinctions, the genetic disparity between us is just around 2%, which means you are actually 98% similar to a chimpanzee.
This small percentage of difference translates to tens of millions of differences in the DNA code, mainly affecting genes and their regulation. While some genes show variations, others remain surprisingly similar, particularly those involved in brain development.
The complexity of our brains doesn't come from unique genes but from the quantity and interactions of neurons. This shows how slight genetic variations can lead to significant differences between species, shaping traits and behaviors, making one species a chimpanzee while the other is a human.
As species evolve, genes can disappear or stop working. Most mammals can make their own Vitamin C, but humans lost this ability in the past because a gene related to it became inactive.
Dr. Michael Jensen-Seaman, a genetics expert, explains that when a species no longer needs a gene, it can vanish over time. For humans, this happened because our ancestors likely ate so much fruit that making Vitamin C wasn't necessary.
Similarly, humans have lost many odorant receptors, affecting our sense of smell, possibly because we rely more on vision than other animals. This shows how evolution shapes organisms by altering their genetic makeup based on their needs and environment.
Some studies have also shown that humans used to have a tailbone, which they used to climb on trees. Due to the inactivity of the tailbone, the genes vanished over time. It happened almost 20 million years ago as an important evolutionary change in humans.
Cephalopods like squids, cuttlefish, and octopuses are known for their remarkable intelligence. They possess the ability to rewrite the genetic information in their neurons, a process called recoding. Unlike most organisms where one gene produces one protein, in cephalopods, one gene can generate multiple proteins.
This unique ability allows certain Antarctic species to maintain their nerve function in extremely cold waters. Scientists have found this adaptation fascinating as it demonstrates how cephalopods have evolved to thrive in diverse and challenging environments.
Despite medical progress, there could be a limit to how long humans can live due to our genes. Research indicates that the maximum lifespan for humans might be between 115 and 125 years. This limitation is thought to be related to the number of times our cells can divide and the damage they accumulate over time.
Even with gene therapy, it's unlikely we can change our genes fast enough to significantly extend our lifespan, as explained by Judith Campisi from the Buck Institute for Research on Aging. This suggests that our biological makeup may prevent us from living much longer than currently observed maximum ages.
You might think that the DNA molecule is miniscule to fit into the nucleus of our cell, but that’s not true. To your surprise, if you were to line up all the DNA molecules in your body end to end, they would stretch from the Earth to the Sun and back over 600 times.
This incredible distance is calculated by taking the number of DNA molecules in the body (around 100 trillion) multiplied by the average length of a DNA molecule (about six feet), and then dividing by the distance from the Earth to the Sun (approximately 92 million miles).
In the animal kingdom, genes related to sperm are evolving rapidly, especially those involved in sperm competition. These genes, known as sperm competition genes, are becoming more effective at fertilizing eggs in various species, including some primates and marine invertebrates.
For instance, in promiscuous primates like chimpanzees, where females mate with multiple males, there's a genetic competition among males to father offspring. This leads to an arms race among genes related to sperm production and male reproduction, where proteins in these genes adapt to improve male reproductive success. This highlights the nature of evolution, where genes undergo changes to meet the challenges of reproduction in different species.
Recent studies have shown that it's possible to extract animal DNA from the air. Scientists collected air samples from zoos in the UK and Denmark and analyzed the DNA within them. In a Danish forest, almost 64 DNA traces of different animal species were found.
Scientists also discovered fragments of DNA from various zoo animals, local wildlife, and even species used as food for zoo animals, like fish. Interestingly, some of the animals detected were located hundreds of meters away from where the air was sampled.
This research demonstrates the potential of environmental DNA (eDNA) studies, which have gained momentum in the last decade due to advancements in sequencing technology. Scientists hope that eDNA can be used to monitor biodiversity and protect endangered species by analyzing DNA samples from surfaces, soils, water, and now, even the air.
It's fascinating to learn that the majority of the cells in our bodies aren't actually human cells. Instead, we harbor a vast number of bacterial cells, estimated to be around 38 trillion. However, the number of human cells is only 30 trillion. So, does it make us more bacteria than humans?
These microscopic inhabitants form what's known as the microbiome reside in our gut, skin, and other mucosal surfaces. They play crucial roles in digesting food, protecting against infections, and interacting with our immune system, without which our bodies couldn't function properly.
In fact, our bodies have evolved to produce sugars in breast milk that nourish these beneficial bacteria in a newborn's gut. This relationship makes us 'holobionts,' consisting of the human host along with hundreds of different species of bacteria, viruses, and fungi coexisting within us.
While bacteria are much smaller than human cells, their collective genetic material contains far more genes (150 times higher) than the human genome.
It's incredible to think that just a few grams of DNA could potentially hold all the data in the world, and this might become economically feasible soon.
In 2013, researchers at EMBL's European Bioinformatics Institute (EMBL-EBI) successfully stored, retrieved and reproduced over 5 million bits of data using DNA. This included Shakespeare's sonnets, a photo, an audio clip of Martin Luther King's famous speech, and scientific papers. By converting files into DNA code and synthesizing it, they stored the information. Retrieving the data involved sequencing the DNA and reconstructing the original files with perfect accuracy.
This DNA-based storage method has the potential to scale up to store all the world's information because DNA is highly durable and compact. In fact, it was estimated in 2012 that the entire world's data at that time could fit into about four grams of DNA, making it the most economical storage option.
The knowledge of genes and genetics is ever-evolving. With the passage of time, scientists have discovered more than what we could not imagine a few years ago. As more time passes, our horizons broaden. Biology is an up-to-date field that keeps you on your toes if you’re studying with highly experienced tutors.
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