“Just like two peas in a pod,” they say, when they see two people who are really close, or even people who are really similar to each other. Peas have a lot of significance when it comes to genetics as biology tends to mention these adorable veggies especially when students are learning about genes and how one trait tends to be dominant while the recessive; we will get to this in a short while.
However, peas are not just delicious enough to eat, they hold a lot of importance in biology and when it comes to biopsychology which takes into account the biological perspective in relation to psychology, pea plants and especially Mendel is bound to make an appearance.
Mendel and the Peas
Considering the influence of peas in the biological world, it is no question that peas would be giving an explanation regarding the psychological disorders or other conditions. People suffering from psychological ailments often question as to why they are suffering from such a condition. And believe it or not, we owe to the genes that make up who we are.
*Sigh* If only we could choose our genes.
Well the ability to choose your own genes is becoming a possibility now as technology advances, but a few years back it was not possible, but people like Gregor Mendel gave us an explanation as to how Inheritance works and we get the genes that we have.
Gregor Mendel was a monk who is also known as the father of genetics as he made some interesting discoveries about how the laws of inheritance work. He came up with two assumptions when he was working with pea plants; the first one being that there are certain number of Dichotomous Traits which do not occur in a combination. For example, if your mother has blue eyes and your father has brown eyes, then you will inherit either one of the eye colors and not both, unless you have a rare genetic condition known as Heterochromia where both of your eyes are of different colors. And the second assumption that Mendel came up with is known as True Breeding Lines, which is when a trait occurs generation after generation, take your hair color as an example.
Occurrence of Inheritance
Now that we have established the two assumptions proposed by Mendel in regards to how traits are sometimes dichotomous and other times are pure breeding lines, we come down to how a trait is ether dominant or recessive.
In school, when learning about genes our teachers taught us the Punnett Squares which helps us understand how a trait is either dominant or recessive. And that is how we know that why three of our siblings have the same trait while the fourth one is the odd one out. Not because he or she is adopted but because of the laws of inheritance, no matter how much we want the former to be true.
The picture above is an example of a Punnett Square. The parents are placed outside the square and the products of the combination of the parent alleles are placed in the four small squares respectively. And this was the basis of the inheritance law proposed by Mendel.
The conclusion which was drawn from all this was that there are two inherited factors for each trait which are known as genes; one factor is dominant while the other is recessive. The dominant factor being the one which is present in the majority and which is likely to occur, while the recessive trait is the one which is less likely to occur.
Furthermore, the chromosomes which contain the DNA are bound in pairs, and they could either be Homozygous pairs which is when the genes have the same dominant or recessive allele, or they could be Heterozygous in nature which is when the genes have different alleles. And the combinations of our DNA makeup make up who we are, not only internally but externally as well, which leads to what is known as Genotype and Phenotype.
Genotype happens to be the genetic makeup of any living thing. No one is said to have the genotype as everybody has a different genetic code; even identical twins tend to have differences in genetic makeup, and that is what makes us unique.
Phenotype is our outward appearance and the traits which can be observed by other people such as our height, hair and eye colors. There can be similarities in phenotypes but the basis of it would be different. And this just adds to the diversity which makes the world colorful and unique.
Food for Thought
As Mendel was curious enough to figure out the laws of inheritance, let’s take inspiration from him and answer this question:
- Keeping in mind Mendel’s experiment and the assumptions he came up with, how would you conduct this experiment?
Lecture 4: Inheritance [Class Notes]
Image by <a href=”https://pixabay.com/users/ruslanababenko-4806232/?utm_source=link-attribution&utm_medium=referral&utm_campaign=image&utm_content=2469490″>Ruslana Babenko</a> from <a href=”https://pixabay.com/?utm_source=link-attribution&utm_medium=referral&utm_campaign=image&utm_content=2469490″>Pixabay</a>