Pleiotropy

Introduction

“Pleiotropy” comes from a Greek word that means “more  ways.” Gregor Johann Mendel, the father of genetics, made many intriguing discoveries about the colour of various plant components. According to Mendel, the plants with coloured seed coats also have coloured leaf axis. He also noticed that the pea plants had white-coloured blooms and colourless seed coats.

Mendel’s observations were based on the outcome of Pleiotropy. When a single gene is involved in a variety of phenotypic features then it is known as pleiotropy. 

Gene Pleiotropy

Pleiotropy of genes is also known as Molecular Gene Pleiotropy. Pleiotropy is a gene that focuses on the number of functions a gene has. Pleitropy occurs when one gene expresses two or more phenotypic traits.

Gene pleiotropy is a gene that focuses on the number of tasks that a single gene can perform. Pleiotropy of molecular genes is another name for it.

We don’t think about phenotypes concerned with the colours of two flowers when we talk about Mendel’s trials with white-coloured flowers and purple-coloured plants. On the other hand, Mendel saw that the colours were invariably linked to two distinct characteristics: the seed coat colour and the colour of the axils.

Plants with white flowers have colourless axils and seed coats, whereas purple blooms have brown-grey seed coats and reddish axils. As a result, the colour gene influences three traits.

Pleiotropic genes govern several and unrelated traits, with pleio referring to many and tropic indicating effects. 

Furthermore, pleiotropic gene alleles are conveyed in the same way that gene alleles affect single attributes. The recessive and dominant forms of the package would be apparent in the offspring of two heterozygotes in a 3:1 ratio, although a phenotypic comprises multiple aspects.

Mendel’s Theory on Gene Pleiotropy

Gregor Mendel, the inventor of genetics, made many intriguing findings of the colour of various plant components while studying heredity. Mendel also noticed that plants with coloured seed coats had coloured leaf axils and coloured flowers. According to Mendel, pea plants likewise had colourless seed coats, no pigmentation on their axils and white blossoms. The colour of the seed coat was traditionally linked to the colour of the axil and blossom.

Presently, we know that Mendel’s findings were based on pleiotropy, a phenomenon in which a single gene is involved in several phenotypic traits. The seed coat colour gene was not the only one responsible for the colour of the seed coat, but also the pigmentation of the axils and the flower.

Examples of Pleiotropy

Phenylketonuria is an autosomal recessive disorder that is caused by a lack of phenylalanine metabolism in the bodily cells. A deficit of the enzyme phenyl aniline hydroxylase, which is required to convert the critical amino acid phenyl aniline to tyrosine, causes this illness. A lack of aniline hydroxylase causes pain, lung disease, eczema, and other symptoms.

Human Genetic Disorders

Pleiotropic genes are influenced mainly by human genetic diseases. For example, a person with the inherited illness Marfan syndrome may experience a variety of unrelated symptoms, such as:

• Extremely tall stature
• An eye lens that has dislocated
• Fingers and toes that are slender
• Heart problems such as aorta ruptures are big blood vessels that convey blood away from the heart

Starch in the pea 

The symptoms listed above may not appear related, yet they can be traced back to a single gene mutation. This gene produces fibrils that provide flexibility and strength to the body’s connective tissues by encoding a protein into chains. Marfan syndrome is caused by mutations that reduce the quantity of functional protein produced by the body, resulting in fewer fibrils.

As genes are co-opted for new purposes, pleiotropic genes can reveal vital information about the evolution of distinct genes and gene families. Pleiotropy, in other words, refers to the fact that most proteins have several roles in different cell types. Any genetic variation that causes a change in gene expression and function can have a wide range of consequences in various tissues.

Conclusion 

Hopefully, you’ve grasped the pleiotropy definition, pleiotropy classification, stages, and other aspects. Pleiotropic genes are genes which control more than one phenotypic trait.