IF YOU DON'T KNOW, ASK MOM AND DAD!
Human genetics is the study of human genes, genetic diversity (variation), and heredity (how traits are inherited from generation to generation). genetics is a sub-science, branch, of field of biology. Chromosomes are structures within the nuclei of a cells (center of the cell). The chromosome has four arms. two are shorter (p arms) and two are longer (q arms).
The centromere of the chromosome holds the p and q arms together. DNA molecules are located at the tips of the arms. These sections that include the DNA act as caps to the arms. The telomere has an important influence in genetics, left alone for a separate blog post...
Deoxyribonucleic acid (DNA), carries the genetic instructions for our development, functioning, growth and reproduction in sub-structure of DNA known as genes. Genes act as "blueprints" for the processes mentioned above, and more. A distinctive result of carrying out the genetic information of a gene, a process called "gene expression" is the creation of proteins. Proteins in turn, govern crucial aspects of function and thus life.
Contrary to belief, diversity in the human population is based on only approximately a 1% difference between the DNA of two people. meaning the people are identical in the other 99% or so. Yet, the human race (the only race that really matters on Earth) considers itself as very diverse, leading to the conclusion that it does not take extensive differences in the human DNA to create an abundance of diversity.
As a matter of principle, your DNA and your genes set the potential for diverse phenomena, yet there are several processes, reactions, and influencers, that could cause that potential to not be expressed completely, accurately, or be expressed partially. Genetics always begs the question "what determines what you see in the mirror?"
People mistakenly tend to think that everything in their body, and for that reason, everything they see in the mirror, is determined genetically, and by their biological parents. This is not the case, as environmental factors that are not heavily influenced by genetic factors, if at all, can influence the outcome analyzed.
Humans have twenty-two pairs of numbered chromosomes (autosomes) and one pair of sex chromosomes represented by the letter combinations of XX or XY, for a total of 46 chromosome, 23 from each parent. Each pair contains two chromosomes, one coming from each parent, which means that children inherit half of their chromosomes from their mother and half from their father.
Men have one Y chromosome and one X chromosome (XY), while women have two X chromosomes (XX). Contrary to thousands of years of blaming the mother, the father determines the sex of the baby under normal conditions. The chromosomes of your parents have been inherited from their parents as well (your grandparents). Collectively, a person's parents have been influenced by four different people.
Traits that you might present, meaning that they have been genetically expressed, or potential traits that exist in your DNA, but are not genetically expressed, could exist in you and originate from people in your family tree from seven generation before you (not including yourself). If we represent you as "generation 0", your parents as "generation 1" to influence you, your grandparents as "generation 2" to influence you, etc., then going back seven generations before you, we identify 128 different people from both mom's and dad's sides combined, that you may have inherited a trait from.
Commonly agreed that a generation spans 20 - 30 years means that you may have traits that have been passed on from generation to generation, all the way down to you, by people that have lived 140 - 210 years before you were born. With people choosing now days to become parents rather later than earlier, and life span increasing, this could mean that traits in the future could be inherited by people that have lived up to 300 years prior to the person that inherits the traits.
While statistically improbable, you may actually have a trait that is expressed now in you, yet has never been expressed before in your family, yet has been passed through the family DNA for hundreds of years. For example, blue eyes in a child to a family that had no one born with blue eyes in generations. This is rare, but possible within the seven generations discussed. Remember: the rule of genetics is that "improbable is not yet impossible". besides, everyone knows that "everything is impossible, until it happens once".
In summary, your family and especially, your parents set the potential for their children to inherit certain traits, yet not all possible versions of their genetic information will actually occur (be expressed). In the coming posts related to genetics, we will dive deeper and deeper into human genetics, and explain what determines "what you see in the mirror". To be continued from one "post generation" to the next. Stay tuned...
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