Left-Handedness Essay

Hand preference or handedness is the ability to use one hand more comfortably and skilled than the other hand for simple tasks such as writing or opening a door. A common belief that many people believe in, is the myth that left-handedness is a recessive gene and right-handedness is a dominant gene.

According to Genetics Home Reference, about 12% of people in the world are left-handed (Reference, Genetics. 2015). This number varies in various cultures. For example, 13.1% of people are left handed in Germany whereas only 2.0% of people are left handed in South Korea (LeftyFretz. 2017). Right handed people have dominated for over 500,000 years and they continue to out-number left handed people. (Siowfa15. 2015). Evidence has proven, by examining the tools used as well as the cave art, that the Neanderthals preferred using their right hands.

Handedness is often explained as polygenic because if it were to be monogenic, two left handed individuals

Is the inheritance of the widow’s peak monogenic?

Hypotheses

Handedness is a polygenic trait as it is affected by multiple genes and external factors. Right-handedness is dominant in my family in the sense that only three out of thirty people are left-handed.

Widow’s peak is a monogenic inheritance. This is a common trait expressed in the maternal side of my family (i.e. my mother’s side of the family). The widow’s peak phenomenon is absent (phenotypically) in my dad’s side of the family.

Method to conducting a survey

Both the monogenic and polygenic pedigree charts will have:

• 30 people in my family that will take part in this project

• 3 generations

I will ask every member of my family about which hand they write with and illustrate the recorded results in a pedigree chart. In the pedigree chart, the individuals that prefer their left hand will be shaded in black – purely for convenience. Pictures will not be