Hereditary

Hereditary

Introduction:

My topic is "hereditary." I have always been interested in genetics,

and this is a large branch of genetics. In this report I also plan to speak

about evolution. I would like to learn more about what causes specific

traits and what the future might bring.

Body:

A person gets his or her traits from their parents. These traits

include everything from the person's sex to their mental abilities or

problems. These traits are hereditary because they are passed on through

genes. They get these genes from their parents and grandparents. They may

inherit innate abilities of their parents, such as an affinity for music.

Another factor in who you are is the environment you live in. The

environment you are in may affect how you develop. For instance, if you

have a talent for music, but have no way to acquire instruments, then it is

doubtful that you will ever discover your talent with music. Physically,

you may have great potential as a runner, but, if you do not get enough to

eat, then it is doubtful that you will ever live up to your potential.

Traits such as what you look like are inherited from your parents.

Your potential is also inherited from your parents. Chromosomes contain the

information of a person's potential height, potential strength against

disease, and other physical characteristics.

A human being has 23 pairs of chromosomes in every cell in his or her

body (except reproductive cells). If, during a stage of growth, a fetus

somehow loses one of these chromosomes, the baby may die, or have a birth

defect. Since this error is written on their genes, they may pass it on to

their children, who may or may not have anything wrong with them.

The way a person looks, as I have stated, is hereditary. In humans,

brown eyes are dominant. Thus, if a person with brown eyes and a recessive

blue eye gene were to marry someone with similar genes, it is most likely

their children would have brown eyes. A chart is used to show the

possibilities:

A diagram like that could be used to find out what the eyes of a

couples children would be. The reason "B" is capitalized is because it is a

dominant trait, and the reason "b" is not capitalized is because it is a

recessive trait.

Thus the possible combinations are BB (25% chance), or pure brown eyes,

Bb (50% chance), or a hybrid whose children may have blue eyes, or bb (25%

chance), or pure blue eyes. There is a 75% chance that the child will have

brown eyes.

The same chart may be used for a number of traits, but in higher

animals, such as humans, there are variations. For instance if a person who

has light brown eyes has a child with a person who has dark brown eyes, the

child's eyes are likely to be medium brown. The charts are still valid

though, because not all traits are compatible.

Recessive genes do not visibly show up when there is a dominant gene

present. A hybrid is a person who has both a dominant and recessive gene.

Their appearance is that of a person who has no recessive gene, but they

carry