The Basic Bits: Genetics is the study of heredity and variation. Heredity is the action of the parents giving their child their different traits, which are called genes. Genes are made from two alleles, one from the mother and one from the father. Each of the genes and alleles have the possibility of being recessive or dominant.
Gregor Mendel was the start of the field of genetics. He was a monk who tended to the peas they grew at the monastery, and at one point he began to recognize that their flowers were changing color. He became curious and started to look around for answers, even cross breeding some of the seeds at one point. This is why we call him the Father of Genetics.
This is a Punnet Square. This is used when trying to find the offspring of two parents. You basically cross multiply the alleles to find the chances of having a certain allele. With these, you find the percent of a certain possibility of your offspring. A capital letter stands for a dominant allele whereas a lowercase letter stands for a recessive allele.
So, we know how we get our letters, which are known as our genes, or genotypes, but how do these letters show themselves in real life? The way different traits present themselves on the outside are known as phenotypes. In this example, the phenotype would be either brown or blonde hair.
Mendel’s Principle of dominance: A well known principle when it comes to dominant and recessive genes, The principle states that recessive alleles can still show up in someone’s genes even if you cannot see them. They have the potential to show through a dominant gene in the next generation.
Incomplete dominance is when two dominant genes basically mush together and create one. Co-dominance is when two dominant genes both show through. This is represented above.
You have a total of 23 pairs of chromosomes. 1-22 are called autosomes. These determine every factor aside from your sex. While one’s 23rd chromosome is a sex chromosome, determining the gender of an infant. Remember, males are the parents who determine the gender of the child, since they are in possession of the Y chromosome. Within the chromosomes, certain traits are passed along from the parents to their child, or sex linked traits. These are traits that either parent has. These could be certain traits such as colorblindness, baldness, lack of sweat glands, etc. These are often found more in males than females, and can be predicted in a Punnet Square.
This shows the different blood types, their genotypes and how much of the population has that specific type.
Blood typing is a very important subject. If you were ever to need to get a blood transfusion at the hospital because you lost too much blood, it would be imperative for the doctors to know what blood type you are. Also, when mothers are pregnant, it is also very necessary to know the fetus's blood type in case the mother's body is incompatible. the chart above shows the different type of blood types. It also shows how they would be shown in a Punnet Square if trying to determine which blood type a child would receive.
This is an example of how blood typing would work in a punnet square.