LET'S BRIDGE OUR DIFFERENCES!
Genes are structure within our human DNA, they serve as the blueprints for the expression of traits in a person through a process known as gene expression. A gene that is expressed will cause the trait that it codes for, to appear and happen. A gene that is not expressed, will not cause the trait that it codes for to happen, thus it will not happen though the potential existed.
Genes can have different variations to them, that will cause from slight to extensive differences in the end-result seen or created. When a gene has more than one version to it (alternative forms), it is said to have more than one allele. As a result, the allele can be defined one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
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Examples of how alleles of the same gene create diversity can include shape, color, size, location, and more. Thus, the gene that codes for human eyes, has several known variations (alleles) that create diversity of eye color. These different alleles allow humans to enjoy the genetic potential for blue eyes, brown eyes, green eyes, grey eyes, and black eyes. Each allele allows and genetically codes for one of the colors.
The gene that codes for human hair type, has several known variations (alleles) that create diversity of how your hair looks. These different alleles allow humans to enjoy the genetic potential for straight, wavy, curly, and tightly curled hair. Often, what we see is the result of combinations of alleles and genes, meaning the trait is a complex trait. The more characteristics a certain trait has, the more complex it is, and the more genes and their alleles can be of influence.
For example, a person's hair can be characterized in several different ways. The color, type, thickness, density, and areas of growth can lead to people looking different just based on their hair. Each characteristic depends on a gene and its alleles. For each gene, each parent can offer two alleles that can be the same of different. Thus, the parents can offer up to four different alleles per trait, if none of the parents alleles are the same.
For example, the mother carries the genetic variations (alleles) for blue and green eye color, while the father carries the genetic variations (alleles) for brown and black eye color. In another scenario the parents may offer only the potential for three eye colors. For example, two out of the four alleles are the same, while the other two are different. A third option is for the parents to offer only two potential eye colors. In this case, each parent has the same alleles as the other parent, yet each parents alleles are different from each other.
An example would be the mother have the alleles for green and brown eyes, while the father has the same two alleles. The last option is that the parents only offer one potential eye color since all four of their alleles are the same. For example, the mother's two alleles are for brown eyes, and the father's two alleles are for brown eyes. In such a case, their children will always have brown eyes.
Thus, the conclusions arising thus far are that alleles are genetic "tools" of diversity. The more diverse the alleles passed on from generation to generation, and the more diversity of alleles per trait, the greater the chances of diversity in the general population. Isolated populations tend to "tap in" to the same "gene pool" reducing the chances for a diverse population. The more options a person has to choose a mate from a diverse population, the greater the chances of a diverse population resulted.
Based on the same principle, the more diversity in the parents alleles, the greater the chances that their children will not look alike, and vice versa. For example, if both parents carry only the allele for brown curly hair and brown eyes, all children to these specific parents will have brown curly hair with brown eyes.
On the other hand, if the parents carry the alleles for straight, wavy, curly, and tightly curled hair, and the alleles for blue, green, brown, and black eyes, the number of possible appearances for their kids, is maximized as it relates to the combination of hair and eyes and their influence on the children's' appearance. Now imagine that the parents also carry four different alleles for nose size and shape, and how many more options were just created for the children to look different from each other.
With that said, there are alleles that tend to be expressed (happen) more than others. When an allele tends to be expressed more, it results in a dominant trait with a greater chances of happening. Alleles with lower tendencies to be expressed are recessive traits with lesser chances of happening. Though, the fact that a trait is dominant does not assure 100% of genetic expression, just as a trait being recessive does not mean no chances of being genetically expressed. As a rule of thumb. darker colors get expressed more (excluding black eyes), while brighter colors are expressed less.
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