The answer is; the melanin in darkly pigmented skin protects DNA from UV radiation, and UV radiation can cause skin cancer
In Africa, due to its equatorial latitude location, receives direct sunlight at more or less 90 degrees most of the year. These highly concentrated rays increase the UV radiation exposure that can cause damage to cell DNA. Selection pressure, therefore, favored individuals with high melanin concentrations that protect against UV. Therefore population evolved towards high melanin densities in the skin.
Answer:
It has incomparable advantages over other gene editing tools.
Explanation:
For example, the CRISPR-Cas9 system has more target sites than ZFNs and TALENs, and Cas9 has many variants that can be used in a variety of studies. Moreover, the system is extremely easy to use and can be executed in almost any laboratory.
The most important advantages of CRISPR/Cas9 over other genome editing technologies is its simplicity and efficiency. Since it can be applied directly in embryo, CRISPR/Cas9 reduces the time required to modify target genes compared to gene targeting technologies based on the use of embryonic stem (ES) cells.
Disadvantages of CRISPR technology: CRISPR-Cas9 off-target; The effect of off-target can alter the function of a gene and may result in genomic instability, hindering it prospective and application in clinical procedure.
this the best i got, hope it helps :)
Cells don't grow very big because they have to be able to diffuse through material easily. Also, when cells are small and plentiful they are easy to replace when damaged.
