It’s a layer located outside of the cell envelope
Chromosomes, which are found in the nucleus of a cell, contain genes. A gene is basically a section of DNA, which carries some type of coding for particular protein. The structure in which all genetic information can be found is your DNA (short for D<span>eoxyribonucleic Acid). (I don't know if the first part helped?).</span>
Answer: To have enough DNA for each gamete, the DNA in the germ cell must be <u>Doubled (x2).</u>
Hope this helps!
After hundreds or even thousands of generations both alleles for sickle cell anemia are still common in those of African ancestry. This is supported by two mechanisms: heterozygote advantage and gene flow.
Heterozygote advantage
When an allele is said to be heterozygous, it is carrying one copy of a gene. For example if one carries a copy of sickle cell allele, it will stay in the population even after many generations — natural selection will not be able to remove it and it will be passed on through generations. So, having one copy of that allele is advantageous but not deleterious.
Gene flow
With humans migrating throughout the different parts of the world, sickle cell allele is passed from one person to another or in different populations. It is actually advantageous to have one copy of this allele especially if there’s malaria in the area, which the allele is resistant.
