Question

From Wikipedia

The haploid human genome (23 chromosomes) is about 3 billion base pairs long and contains around 30,000 genes.[33] Since every base pair can be coded by 2 bits, this is about 750 megabytes of data. An individual somatic (diploid) cell contains twice this amount, that is, about 6 billion base pairs. Men have fewer than women because the Y chromosome is about 57 million base pairs whereas the X is about 156 million. Since individual genomes vary in sequence by less than 1% from each other, the variations of a given human's genome from a common reference can be losslessly compressed to roughly 4 megabytes.

Why do humans share over 99% of their genomes? Is it a historical accident or a result of selective pressure? If a zygote differed in 5% of the base sequence from the common human genome would it automatically be unviable or could it eventually become a healthy baby?

Answer 1

The human genome consists of 3 billion base pairs and over 20,000 genes spread among 23 pairs of chromosomes. Humans share over 99% of their genomes due to selective pressure. A zygote with significant differences from the common human genome is less likely to develop into a healthy baby.

Step-by-step explanation:

The human genome consists of about 3 billion base pairs of DNA. This DNA is divided into more than 20,000 genes spread among the 23 pairs of chromosomes. Humans share over 99% of their genomes due to selective pressure, not a historical accident.

If a zygote differed in 5% of the base sequence from the common human genome, it would not automatically be unviable. However, significant differences in the genome can lead to genetic disorders or health issues. In general, a zygote with a large number of differences from the common human genome is less likely to develop into a healthy baby.