Zainab Ilyas

· 29 Dec 2021

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How many chromosomes does human have?

Each cell in the human body has 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairings, referred to as autosomes, are identical in males and females. The sex chromosomes, the 23rd pair, differ between males and females.

Chromosomes the building blocks of you:

There are trillions of tiny cells in the human body that contain everything that allows our bodies to operate. All of your chromosomes are housed in the nucleus of those cells, which you might think of as the cell's command centre. A chromosome is a DNA chain with a set of proteins that help it stay together. Your genome, or entire set of genes and genetic information, is inscribed on 23 pairs of chromosomes, for a total of 46 chromosomes. What are the origins of these chromosomes? So, when you were conceived, your mother gave you half of your chromosomes and your father gave you the other half.

Chromosomes are essential for cell eyesight because they package your DNA into tight coils. They also house your whole genetic sequence, which is what makes you who you are.

Unraveling chromosomes

When you unwind a chromosome, you'll notice that it has a thread-like structure. If you peel back the layers of your DNA, you'll find clumps of proteins called histones coiled around your DNA.

DNA is a molecule that is unlike any other. Its atoms create a spiralling ladder that serves as the genetic code for all living organisms. The threads that hold the helix together are made up of four kinds of nucleotides: adenine, guanine, cytosine, and tyrosine. Nucleotides are the building blocks of proteins, which are then used to make all of the tissues and organs that allow you to breathe, see, hear, and interact with the world around you.

Chromosomes are generally shown as two sausage-like forms joined by a centromere, or midway. The bulk of the time, however, DNA is found in its natural state - as a lengthy, disordered, and tangled ball of yarn hidden away within the nucleus of the cell. The chromosomes only condense into a tidy spool when the cell has to replicate during mitosis. This structure offers a long-lasting and useful structure that permits the DNA to break evenly.

How chromosomes make us all a little bit (or extremely) different

But how can chromosomes play a part in distinguishing you from your sibling or sister? Or, much better, from an elephant or a dog?

Genetic mutations, or a permanent modification of a fragment of DNA that makes up a gene, are to blame for these alterations. There are two basic mechanisms in which these mutations might occur. Hereditary mutations are passed down from your parents and can be found in every cell of your body throughout your life. Perhaps your entire family is lactose intolerant, or you're all redheads with blue eyes. These mutations will remain in your chromosomes for the rest of your life and can be handed down to your offspring. According to studies, parents pass on an average of 60 genetic variations to their children, all of which contribute to the physical or behavioural traits that distinguish you from your contemporaries. There are also acquired mutations, which arise at some time in your life and affect only a subset of your cells. These might happen as a result of cell division or external causes like pollution.

The number of chromosomes in an organism also aids in differentiating it from other species. Humans have 46 chromosomes that are organised into 23 pairs, as previously stated. Both the Reeves' muntjac and the antelope have 46 chromosomes. Potatoes, gorillas, and deer mice all have 48 chromosomes, which may come as a surprise. Carp, rattlesnake fern, and black mulberry all contain 104 chromosomes, although rattlesnake fern has 184 and black mulberry has 308. Clearly, the number of chromosomes does not correspond to the organism's apparent complexity. Furthermore, the number of chromosomes alone is insufficient to define species.

In truth, the number of chromosomes in a plant or animal is decided entirely by chance. Chromosome counts can drop or increase due to fusion or polyploidy, resulting in emerging species having a different number of chromosomes than their forefathers. Fusion happens when two chromosomes accidentally join together, and it is the most plausible explanation for how chimps developed into humans. Human chromosome 2 has been discovered to resemble two chimp chromosomes fused together, suggesting that this is how we evolved from our monkey cousins to the humans we are today.

Polyploidy, on the other hand, is caused by a cellular division mistake. Meiosis is the process by which sperm and eggs, or sex cells, divide. The DNA is condensed into compact chromosomal bundles during this process, and the chromosomes are dragged to opposing ends of the cell, which splits into two new cells. Sometimes chromosomes are not correctly torn apart, resulting in a new cell with more chromosomes than normal. If a sperm fertilises this cell, the resulting creature will have more chromosomes than its forerunners. This is frequently a catastrophic mistake in humans, and the foetus does not survive. Polyploidy can occur in a variety of non-vertebrates, including flatworms and leeches, as well as numerous plants.

Chromosomes: The spice of life

DNA replication and variety in humans and other species would be lost without chromosomes. These thread-like molecules are required to keep our tangled DNA in check both inside the nucleus and throughout cell division. While the number of chromosomes may not dictate a plant's or animal's evolutionary complexity, the genes that the chromosomes contain do. The genetic information contained within chromosomes is what distinguishes you – an entity with 46 chromosomes and around 24,000 genes – from the rest of the species that share this vast planet.

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