How can all the complexities of creating a human being be encoded in just 2.3 gigabytes of DNA data?

Answered Jan 7, 2019

A few issues here.

The information in the human 46 chromosomes is fairly large. Some of this is recycled programming that has been selected for efficiency for billions of years. Basic things like bilateral symmetry body plans (Hox genes), or like glycolysis (a standard series of enzyme reactions), have been refined towards using the least possible resources. The least possible base pairs and protein machinery. Although some things are still obviously kludges and cobbled together.

Processes that were “invented” by bacteria, worms, and insects, going back three billion years ago, are still present in humans.

Some genes have more than one possible product. Their RNA transcripts have multiple possible combinations of exons, known as alternative splicing.

Each individual human also has Epigenetics. On a basic level, this is what tells your liver cells to be different to your skin cells. They all carry the same 46 chromosomes, but the different cell tissue types express the gene sets differently. This uses manipulation of DNA, and also manipulation of histone tail charges.

This starts with cell division, when some proteins have a higher concentration at one end. And that end divides off to become a differentiated type of cell.

A muscle cell and a liver cell and other cell types all contain your full genome. The difference is in which genes are actually expressed (turned on and triggering production of proteins).

Epigenetic changes can be completely normal and basic and necessary. But, sometimes can be hazardous, and caused by exposure to toxins or other things, including malnutrition and psychological stress.

In addition to epigenetics, there are also transcription factors, which look for certain types of genes that are needed at a given moment. They may be triggered by stimulus at the cell membrane, and then go to the nucleus to turn on production of some product that is needed to respond. This is an area of those cobbled-together kludges.

The most complex thing about humans is consciousness, including emotions. It seems unfathomably complex and mysterious. Like A, C, G, and T couldn’t possibly add up to that. But it’s really just an egotistical illusion based on molecules.

My guess is that, the question-asker (or other people who think of this type of issue) may be thinking of spiritual/religious ideas and direction. And I’ll admit to contemplating biology, and seeing it as magical. But it’s more important and realistic to admit that we are just really complicated machines.

Can the DNA remain in a girl after an abortion?

Answered Oct 25

Yes. It is called fetal microchimerism.

Material from the foetus can pass through the placenta, into the mother. This can result in ongoing cell lines which are based on that foetus, with a genome based on both parents, so different to the mother’s own genome. These cell lines can persist for the rest of the woman’s life.

No, you cannot grow a new foetus from these cells.