I need help constructing an explanation for extreme varying heights between humans.
Genetics & Inheritance Humans have many height genes, and scientists have only discovered about 800.
Morning, Dr. C. I don't believe we've met. I am Doctor Who.
Oh, I know you! I would never forget my first doctor.
What can I do for you?
I've heard it is mostly genetics.
I just need to know why there are people who are 9 feet tall and 3 feet tall.
Give me more.
Well, there are many components that factor into height.
While genetics determine 60-80% of a person's maximum height, environmental factors also play a big role in heights of different individuals and even a whole population (National Institute of Health).
Genetics & Inheritance Molecules of the Cell Basic Concepts of Human Evolution
During sexual reproduction, humans pass down a total of 23 pairs of chromosomes - 23 from each parent. These chromosomes are compacted strands of DNA and histone proteins that contain much of a person's genetic information, i.e. genes. Scientists have only discovered a fraction of all height-related genes. Some of these include the FGFR3 and HGMA2 genes (PBS).
When parents have offspring, DNA from either the mother's egg cells or the father's sperm cells could have a mutation. This would cause a mutation in the baby, called a hereditary mutation or a germline mutation, whatever you want to call it. This mutation in DNA could be affecting a height gene. This would cause a variation in the gene, ultimately leading to a height change. In extreme cases, such as the one you are looking into, such variations can be so significant that it becomes very impactful in a person's height (National Institute of Heath).
Offspring w/ Hereditary mutation
A biomolecule is a molecule produced by a living organism. There are four major ones: Proteins, Lipids, Carbohydrates, and Nucleic Acids. The one we will be focusing on is proteins; more specifically, growth hormones, which are proteins made by the pituitary gland, located at the brain's base and put into the bloodstream.
Molecules of the Cell Protein - growth hormone
One of these passed-down genes include GH1, the gene responsible for providing the instructions for producing growth hormone (National Institute of Health).