Countless issues (e.g. ancestry, crime solving, infertility, Autism, Mast Cell Disorder, cloning, genetic modification) are frequently debated on the basis of misinformation, which is sometimes accidental but more often used to promote an agenda. Moreover, it’s nearly impossible to interject truth into an argument in which both sides are starting from a false premise.
Hopefully, the general public can be more informed when discussing and debating genetics. Our understanding will impact both the development and application of ethics in research/ experimentation and subsequently medical care, which are heavily influenced by voting and purchasing or boycotting.
Here are the must-know basics:
The “building blocks” of life– the most basic unit of living organisms– are cells. They provide structure and take in nutrients, which are converted to energy; they also carry out specialized functions. The human body is composed of trillions of body cells that each have 46 chromosomes: 2 (X, Y) determine what sex they are and the rest are 22 pairs of non-sex chromosomes (44 + XY = male; 44 + XX = female).
Chromosomes are made up of strands called DNA: material that every organism inherits, which contains information about what they are (e.g. human, elephant, tulip, snail, oak tree) and what they can do (e.g. lay eggs, photosynthesize).
Sections of DNA are called genes. Each pair of your non-sex chromosomes inherits the same hereditary information: 1 from your mother and 1 from your father.
Similar to the way alphabet letters form words and sentences, genetic information is stored as code made of chemical bases. The order/ sequence of these bases determines what information is available for building and maintenance. Each are paired together to form what looks like rungs of a winding staircase.
DNA copies itself; each coded strand forms a pattern that’s followed in duplication.
Genes are either switched on or off– imagine toggles on a control panel– depending on which information is needed to perform a particular function. Each kid of tissue in the human body does something different; not all functions are performed by all the same tissue.
Genes can be (de)activated. Sometimes this is done deliberately in a controlled setting (i.e. laboratory) but it can occur accidentally/ unknowingly via environmental conditions, especially if a hereditary predisposition is already present. For example: the installation of hardware is useless without flowing electricity; flipping a light switch needs electricity flowing to it. Likewise, an electrical current doesn’t do much good if on/off switches haven’t been installed in the structure receiving electricity.
Slight variations can occur (less than 1% of a DNA sequence). Some result in a deviation from the average gene, which may develop an atypical protein or an atypical amount of a normal protein. In other words: a gene can experience a mutation, which causes a permanent alteration in a DNA sequence.
In each pair of non-sex chromosomes are 2 copies of each gene: one from each parent. If 1 deviates from average, the other may make enough protein so no trait develops. These gene is considered recessive. In non-sex recessive inheritance, parents may not show any sign of the particular trait. They are considered “carriers.”
If 2 copies of an atypical gene are present, a particular trait may develop. If 1 atypical gene is needed for a trait, it produces that dominant hereditary trait. Thus, if 1 of these atypical genes is inherited, the offspring will likely exhibit that trait.
Resessive and dominant traits can be as simple as red hair or as complex as disease.
Single- gene disorders, such as Cystic Fibrosis and Sickle Cell Anemia are rare. Chromosomal disorders, such as Down Syndrome are slightly more common. Multifactorial disorders, such as Asthma, Cancer and Diabetes are relatively common.
Cloning produces a genetically identical copy of a biological individual. Some organisms, such as bacteria, naturally reproduce copies of themselves rather than lay eggs. Natural cloning can occur in humans and animals, which results in identical (but not fraternal) twins.
The two most common applications of artificial cloning are “reproductive” for the purposes of copying a whole person or animal (remember now- infamous, Dolly The Sheep?) and “therapeutic” for using stem cells to replace damaged tissue.
To educate yourself beyond the basics outlined above, start by consulting the following:
Introduction to Genetics