• Shruti GOCHHWAL

HUMAN BEING’S CLOSEST RELATIVE

INTRODUCTION

The chimpanzee and the bonobo are human being’s closest living relatives!

We are part of the greater apes family and thus more closely related to the Gorilla, Orangutan, and Chimpanzee rather than the gibbons and the monkeys. The greater apes have a larger brain, bigger body, and lack tail.

One of the biggest misgivings is humans having evolved from chimpanzees. However, that is not true as both humans and chimpanzees share a common ancestor some 5-6 million years old. Chimpanzees are the closest genetically to humans sharing about 98.6% of our DNA. Just a mere difference of 2% in DNA and a vast difference in physical, neurological characteristics, and behavior. Chimpanzees are excellent climbers, live social lives, participate in power politics, are ingenious in the making and usage of tools, and are even known to show betrayal and commit homicide. Yet these behaviors don’t remotely come close to the complexity and nuance of human behavior. The chimpanzees are near-incapable of spirituality, irony, or even sarcasm.

GENETIC MAKEUP

GENETIC MAKEUP

It was just a few years ago with the human genome project that the sequencing of the human genome was completed and soon after the chimpanzee’s DNA was also sequenced which confirmed the similarity to our DNA.

Their DNA consists mainly of 4 components namely Adenine, Guanine, Cytosine, and Thymine. Even an error as small as that of a single nucleotide can result in a mutation. It is this difference which when passed down for generations leads to a DNA difference between species. Therefore in genomes which includes hundreds of millions of nucleotides even a small interval of 2% translates into millions of nucleotide differences.

Important to understand here is that the bodybuilding material or ‘proteins’ are made from genes which is nothing but a sequence of nucleotides put together. Now, DNA is divided into useful parts (which encode for extrons of RNA and thus participate in protein production) and non-useful parts (which encode for introns of RNA and do not participate in protein production). If nucleotide difference is present in the non-coding region no significant difference is caused, however, even a single nucleotide difference present in the coding part can lead to totally different proteins being produced.

DIFFERENCE IN THE GENES

DIFFERENCE IN THE GENES

DIFFERENCE IN THE GENES

In the DNA, important information is stored in a short stretch of nucleotides just before each gene and is also known as the ‘switch’ for the genes. They, in turn, are stimulated by proteins called transcription factors. So say, when you suffer an injury, transcription factors are produced which switch on genes of your fighter cells triggering inflammation. Accurate production of transcription factors is essential and a single nucleotide mutation in the gene producing those factors can turn catastrophic.

One of the biggest differences in genes between humans and chimpanzees come among these transcription factors. Furthermore, gene differences come in the type of activity. Chimpanzees have a lot more genes associated with olfaction(sense of smell), some with the immune system giving them protection against malaria(seeing their main habitat is the forest) but the same make them more vulnerable to tuberculosis as compared to humans. This simply means that some genes are more expressed in one species while it is masked in the others just like when you hone a particular skill it takes precedent over the others.

difference between the two species

THE BIGGEST DIFFERENCE

The brain is the single biggest difference between the two species. After careful examination of a neuron across many species be it humans, chimpanzees, frogs were found not to be different and were made up of the same fibrous dendrites and axon trunk, however, the difference was found in the quantity. It involves things as simple as cell division. Neurons starting from one divides into two, then four, then eight, and so on. It takes about 37 rounds of division to reach the size of the human brain. If the division stops just 2 steps less, it gives the equivalent of a chimpanzee brain. So, only a very few genes regulating the rounds of cell division are one of the biggest difference causes between the two species!

So, ultimately the vast difference between human beings and chimpanzees comes down to something as small as a couple of percentage differences in DNA, so next time do remember the power that a couple of percentages of DNA hold!

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