Genetics work through the inheritance of genes, which are units of heredity that determine an organism's characteristics. You receive one copy of each gene from each parent, and these genes influence your traits and your susceptibility to certain diseases.
What are Genes?
Genes are segments of DNA that contain instructions for making specific proteins. These proteins perform various functions within the body, influencing everything from eye color to enzyme production. Think of DNA as an instruction manual, and genes are specific recipes within that manual.
How Genes are Inherited
You inherit half of your genes from your mother and half from your father. These genes are packaged within chromosomes. Humans have 23 pairs of chromosomes, totaling 46. One chromosome of each pair comes from the mother, and the other comes from the father.
How Genes Influence Traits
The specific combination of genes you inherit determines many of your physical characteristics, such as height, hair color, and eye color. Some traits are determined by a single gene (like the ability to roll your tongue), while others are influenced by multiple genes interacting with each other (like height or skin color).
Dominant vs. Recessive Genes
Genes can be either dominant or recessive. A dominant gene will express its trait even if only one copy is present, while a recessive gene will only express its trait if two copies are present. For example, if you inherit a gene for brown eyes (dominant) from one parent and a gene for blue eyes (recessive) from the other parent, you will have brown eyes. You would only have blue eyes if you inherited the blue eye gene from both parents.
Gene Mutations and Disease
Sometimes, genes can undergo mutations, which are changes in the DNA sequence. These mutations can be harmful, beneficial, or have no effect at all. Harmful mutations can lead to genetic disorders or increase the risk of certain diseases, such as cystic fibrosis or sickle cell anemia. The reference highlights how genetics influence whether or not you're susceptible to certain diseases.
Examples of Genetic Influence
- Eye color: Largely determined by genes, although multiple genes contribute to the specific shade.
- Height: Influenced by multiple genes, along with environmental factors like nutrition.
- Risk of heart disease: Certain genes can increase or decrease the risk of developing heart disease.
- Cystic Fibrosis: Is an example of a disease you can inherit via your genes.
Epigenetics
It's also important to note the role of epigenetics, which involves modifications to DNA that can change gene expression without altering the DNA sequence itself. These epigenetic changes can be influenced by environmental factors and can be passed down to future generations.
In summary, genetics works through the inheritance of genes from parents, which determines traits and influences the risk of certain diseases. These genes, composed of DNA, provide instructions for the body and their expression is influenced by both dominant/recessive inheritance and environmental factors.
