Humans and HeredityEvery human organism, though largely similar, displays varying family and individual traits. The information “portfolio” lies in certain macromolecules called DNA. These macromolecules are contained in tiny structures—genes—which are themselves contained in 23 pairs of heredity bearing units—chromosomes.
What Determines Sexuality?Most of the chromosomes—22 of 23 pairs—are found in both male and female and are termed autosomes. The remaining, lone pair are sex chromosomes. In the female, the pair are similar, but not identical, chromosomes. These are called x chromosomes due to their distinctive shape. In the male, the sex chromosomes includes one x chromosome and one differently shaped y chromosome. Since the male can offer either an x or a y chromosome, whereas the female can provide only an x chromosome, it is the male that determines a child’s gender.
Genetic DangersThe Bible indicates the earliest genetic damage occurred as a result of human sin in the Garden of Eden. That genetic damage exists is commonly recognized. Experiments involving radiation demonstrate that fact, as the Department of Energy acknowledges. The National Institutes of Health (NIH) lists dozens of genetic birth defects. One cause of genetic damage is smoking, discussed in an article referenced below, by the Cleveland Clinic Center for Reproductive Medicine. Another danger is assisted reproductive techniques (ART). In fact, there are many sources of genetic damage. Some are chemicals that alter DNA—mutagens. Does the y chromosome possess no protection from external influences?
Y Chromosome Repair MechanismsSince females have two x chromosomes, weakness in one can be compensated for by the second. Such is not the case for a single y chromosome. As a result, all might look like doom and gloom for the y chromosome. Wonderfully, however, the y chromosome possesses a mechanism that ensures errors are overcome. Dr. David C. Page, Director of the Whitehead Institute for Biomedical Research, indicates the y chromosome serves as a “palindrome” of itself. A mirror image of its information is contained within itself. Damage to the chromosome can be fixed by the chromosome itself!
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- Human Genome Project Information
- How Does Radiation Affect Humans?
- Genetics/Birth Defects
- Sperm DNA damage and its clinical relevance in assessing reproductive outcome
- David C. Page, MD