Page 158 - If Darwin Had Known about DNA

Harun Yahya

156

How Genes Control Cell Division and
Growth

One of the genes' most important tasks is controlling how embry-
os develop. Intensive adjustments during this process mean that the di-
viding cell's DNA is copied accurately, that any errors in the DNA are
rectified and that every new-formed cell receives a full complement of
chromosomes. In this process, some genes have various control points
that ensure that errors are checked and that if anything goes wrong, the
process is halted for repairs to be made.

If an irreparable error arises in a new cell's DNA, the pre-pro-
grammed cell death known as apoptosis takes place. By this wide-
spread method, the body gets rid of cells it has no use for. The cells that
self-destruct by apoptosis break apart and are recycled by a kind of
white blood cells known as macrophages. Apoptosis helps protect the
body against genetically impaired cells that might lead to cancer, which
can arise when normal cell division is impaired. Division then takes

place in an uncontrolled and irregular manner, and genetic impair-
ments accumulate, leading to a cancerous tumor. Apoptosis also plays
a very important role in embryonic development and the protection of
adult tissues.
One of the most important discoveries made in molecular biology
is that some genes have more influence than others. They are organized
according to their degrees of empowerment. For example, some genes
are responsible only for fixed tasks such as making hemoglobin, hair

growth or producing digestion enzymes. These molecular workers
have regulator genes, which operate and halt them. During fetal devel-
opment, for example, they stop the hemoglobin gene from working set-
ting it back in motion when necessary. Regulator genes act like super-
visors of both the "worker" and "middle-management" genes. Their de-
cisions affect dozens or even hundreds of lower units; and so vitally im-