Final answer:
Humans have between 20,000 and 22,000 genes, a count that is surprisingly close to that of much simpler organisms. The Human Genome Project revealed that a large portion of DNA is shared among various species. When comparing humans to fruit flies, which have about 15,000 genes, it's clear that complexity in organisms is not solely due to gene count but also due to intricate gene regulation and protein synthesis mechanisms.
Step-by-step explanation:
When comparing the number of genes in the human genome to those of other organisms, one notable fact is that humans have an estimated 20,000 to 22,000 genes. This might seem substantial, but it contrasts with the fact that less complex organisms possess a gene count that is almost comparable to that of humans. One of the astonishing revelations from the Human Genome Project was the sheer percentage of DNA shared between humans and other species, such as chimps, with which we share around 99% of our DNA.
Despite this high count of genes, it is intriguing to note that of the 3 billion base pairs in the human genome, only about 1.5% are actually coding for proteins. The genome's remainder is involved in regulation and other so far less understood functions. Intriguingly, through genomics, it's discovered that species even as different as humans and yeast have a surprising number of genes and DNA sequences in common.
Comparing to a specific organism, consider the fruit fly (Drosophila melanogaster), a model organism often studied in genetics. Drosophila has around 15,000 genes which, while fewer than humans, is still quite high considering its relative simplicity as an organism. The fact that more complex organisms like humans do not have drastically more genes than simpler organisms but have a more sophisticated mechanism of gene regulation and protein synthesis showcases the complexity of evolutionary biology and genomics.