Biology Concepts: Let Me Help You Understand Genetics

The phenotype is the description of the trait. For example: brown eyes, blonde hair, curly hair, etc... The genotype is the genetic code that determines an organism's trait.

What is the sex chromosome for male and female? How can you tell them apart?

The male sex chromosome is a Y. A male has an XY genotype, the X from his mother and the Y father. The female sex chromosome is X. A female has an XX genotype, the females receives an X chromosome from both father and mother.

What does fertilization accomplish?

Fertilization is significant because it adds a second haploid of chromosomes to the cell, in doing so it produces a complete genetic set for the fertilized cell. Fertilization also provides another means of variation in genetic make-up so that there is a little of both mother and father cell in the fertilized cell.

In addition to this, fertilization also causes the cell to grow into an organism by providing what is needed in order for it to become such. We all know the principle of fertilization of an egg with a sperm. This fertilization causes a baby to develop.

How is it that a sexually reproducing individual or organism can look similar to its parents, but not exactly alike?

There are a massive number of genetic combinations from which an organism develops. During meiosis there are 8,388,608 different genetic combinations of the material and fraternal genes. This leaves an awfully big gene pool from which to grab from. The end result is that the organism inherits dominant traits that may look exactly like their parents, or that may only resemble. For example, they may get their father's brown eyes but their mother's curly hair. As such the new individual or organism only resembles their parents instead of looking exactly like them.

Can traits skip a generation?

Yes. There are traits that skip generations. While things like hair and eye color aren't commonly noticed, they can skip a generation. What are very noticeable in science are genetic diseases that skip a generation and affect the next generation. These are called Autosomal Recessive Disorder.

An individual, deformed by accident, can have children who have no such deformities. Why?

The key words to look at here are "by accident." In an accident you are not damaging the DNA. Despite the fact that the body now has a deformity, the DNA does not. Thus, the passed on DNA is normal and will not cause a deformity in the organism.

How does the probability of an outcome differ from the actuality of an outcome?

Probability is the number of possible outcomes. In terms of genetics, probability is the number of possible genetic combinations. For example, an offspring of the genetic combination Gg has the probability of four different genetic outcomes [GG, Gg (from mother), Gg (from father), gg].

Actuality deals with what will actually happen, a fact. In terms of genetics, this means the actual genetic combination that will take place. In the aforementioned situation we cannot tell actuality until the new cell is produced. However, if we were to see mother cell AA combine with Father cell aa, then we can tell that the daughter cell is Aa. This is the actuality, it is fact. We can predict it and tell what will happen. With probability we can only predict the possibilities, what might happen.