Genetics By Shaun Evans and Tiana Miller

This is Gregor Mendel.

Gregor Mendel, considered the Father of Genetics, noticed that some pea plants bloomed different colored flowers than the rest. He decided to breed the flowers, wondering what heredity (traits inherited from the parents) the offspring might have, and kept an accurate record of the offspring. As he noticed repetitive patterns that kept occurring, he began to use statistical data to predict the outcome of his selected breeding. Thus, the study of genetics was born, genetics being the study of heredity and variation.

DNA consists of genes. A gene is a piece of code that determines your traits. Genes are made up of two alleles each, one from your father and one from your mother. Some alleles are dominant and some are recessive. A dominant allele covers a recessive allele. This means that you can have one dominant allele and one recessive allele and only show the dominant one. A carrier is an organism that does not show a genetic disorder or disease, but has a recessive allele that it can pass on to its offspring.

Punnett squares are used to determine the genotype and phenotype of an organism. Genotypes are the genes an organism possesses for a particular trait. Phenotypes are the physical expressions of the traits. There are three types of genotypes: homozygous dominant, homozygous recessive, and heterozygous. Let's say B is a dominant trait and b is a recessive trait. Homozygous dominant would be BB because it has two dominant alleles. Homozygous recessive would be bb because it has two recessive alleles. Heterozygous would be Bb because it has one dominant and one recessive.

Incomplete dominance is when traits blend together because there are multiple dominant genes.
Codominance is when there are multiple dominant genes that contribute equally to the phenotype. This can cause a sharp contrast in appearance.

The human body has 46 chromosomes and these chromosomes come in pairs, making 23 pairs in the body. When looking at the Karyotypes, or chromosomal profile of a person, these chromosomes are arranged in their pairs based on their size.

Not an actual representation of an xy chromosome

The last, and smallest, chromosome (Chromosome 23), otherwise known as the sex-chromosome, determines the gender of the organism. The remaining 22 chromosomes are called the autosomes and will make up everything else about an individual other than the gender. However, traits found specifically on the sex chromosome are called sex-linked chromosomes. These chromosomes differ depending on whether or not the child is male or female. Considering that the male is the deciding factor as to whether or not the child in male or female (as they have the XY sex chromosome while females only have an XX sex chromosome), they are more likely to express sex linked traits

Squares are used to represent males while circles represent females. A shaded in shape represents an affected individual.

Pedigree charts tracks one specific trait pattern through familial generations. Sometimes an organism is bred for specific traits. Cross breeding for a single selected trait is called a monohybrid while one bred for two specific traits is a dihybrid.

The epigenome is the outerlayer of genetic information around the strands of DNA. This serves as a way to separate genetic information and allows specific traits to appear and others to not.

There are 4 blood types that exist in humans: A, B, AB, and O. Your blood type is determined by the type of protein that is present on the surface of your red blood cells. Your blood type also has a Rhesus factor (Rh factor). Your blood can be Rh positive or Rh negative. Most people have Rh positive. Also, a female with Rh negative can only accept a fetus with Rh negative. If she got pregnant with a Rh positive fetus, her body would reject the baby resulting in the death of the fetus and also risk the mother's life.

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