A very common phrase that we often come across in our lives is that “history repeats itself”. While we can’t be sure about whether that’s always true or not, it is science itself that verifies this statement for us. Yes, you heard that right!
Want to know how? Read more to find out!
Concept of Heredity
In terms of the study of Biology, heredity can be simply put as the passing down of characteristics in all forms from one generation to the next. So for instance, the colour of the eyes of your father/mother could be the same as you.
The concept of heredity is applicable to all living forms, which also includes plants as well as animals apart from human beings. It makes the successive generation receive or inherit similar character traits as the generation before them.
What causes hereditary changes?
The very basis of hereditary changes is a result of the unit called the ‘Gene’. In fact, a gene is referred to as the basic unit of heredity. Genes carry the information of those traits that are passed on to you from your previous or your parents’ generation. Genes are made up of DNA and are present in cells as condensed structures called chromosomes.
Human DNA is therefore present in the genes. These formulate and decide the physical, emotional, intellectual and even psychological traits of an individual to a large extent.
Genes And Chromosome
Genes are the fundamental units of heredity carrying information on specific traits of an individual. Since every kind of trait in an individual is different from the other, hence different genes are responsible for different and unique characteristics. The study of genes and heredity is known as ‘Genetics’.
On the other hand, chromosomes are the structure in which these Genes reside. Chromosomes are nothing but the highly condensed form of a very long DNA molecule wrapped around proteins. In fact, a single DNA molecule is approximately 2.2 metres in length! But the highly compact nature of its arrangement allows that entire structure to fit inside the nucleus of a human cell.
There are a total of 23 pairs of chromosomes in each human cell, making it a total of 46 chromosomes in total in each human cell. We inherit 23 chromosomes each from our father and mother resulting in the 46 chromosomes and this explains why children are essentially a combination of the traits and characteristics of their parents. These are very vital components of the human body, as these are the fundamental properties of the human body at large.
Why don’t I have my mom’s nose?
Physical properties like shape of the nose, height, etc. too are completely dependent on the type of genes that have been passed on from the parents. However, it can’t be made sure that the individual gets the desired characteristic property as from their respective parents. It can be identical to their mother’s or their father’s or a combination of both their noses.
Analysing The Underlying Genetics
Now, as we know by now a person inherits one set of chromosomes or 23 chromosomes from their mother and another set from their father. Therefore, they have two copies of every gene in their body. Now, let us take a look at the genes determining the shape of the nose. The gene variant that produces a large nose is referred to as ‘N’ here while the gene variant that corresponds to a small nose is denoted by ‘n’. Since every individual has two copies of a gene, they either possess ‘NN’, ‘nn’, or ‘Nn’. Now, the ‘N’ gene is dominant over the ‘n’ gene which basically means that an individual with the genes ‘Nn’ will have a big nose, the same as a person with the genes ‘NN’. Let’s look at this from a hereditary point of view:
Consider a set of parents; the father has a gene variant of ‘nn’ and the mother has a gene variant of ‘NN’.
N= long nose trait
n= short nose trait
All the children, in this case, will have the gene combination ‘Nn’ (as they will inherit one gene from each parent and since ‘N’ is dominant over ‘n’, all the children will have a big nose.
- Genes can break and even alter with the evolution of an individual! These alterations or changes are known as mutations.
- On A Genetic Level, All Humans Are More Than 99 Percent Identical.
- Our Genes Might Prevent Us From Living More Than 125 Years.
- Where do your genes come from?
- How many chromosomes do humans have?
- Does every person have a unique gene code?
True or False
- DNA is irrelevant in human body. (True/False)
- Genes are contained in cell like structures called Chromosomes. (True/False)
- All cells have DNA. (True/False)
- Humans can completely alter their genes over time. (True/False)
Here’s some more fun questions for you, lets see how many can you answer!