Our genes can be affected by the environment and change the way our traits are displayed, called the phenotype. However, changes in phenotype have an underlying genotypic source. Epigenetics or epigenetic changes are changes in the way traits are expressed as an effect of the environment (i.e. food we ate, chemicals in the body, environmental stresses), without changes in the DNA. Simply put, in epigenetics, some parts of the DNA are turned on or off in response to environmental conditions.
The vector that would be the
best choice for cystic fibrosis gene therapy is adeno-associated virus for it
has valuable reasons. First, it is huge enough to carry the gene, second, it
will infect the right type of tissue, third, it will not cause an immune
response and lastly, it infects the particular cells that divide irregularly. Therefore,
this vector will definitely treat cystic fibrosis for it can target affected
cells, which is a great help in the normal functioning of an organ.
<span> After fertilization, the </span>zygote<span> undergoes cleavage to form the blastula. The blastula, which in some species is a hollow ball of cells, undergoes a process called gastrulation, in which the three germ layers form.</span>
<span>The correct answer is B. Pulmonary. The answers C. Cerebral and D. Extremity, are baseless regarding this question; A. Systemic could be a good alternative, as the blood flows from the systemic to the pulmonary circulation in the right side of the heart; but the systemic circulation is in fact mostly handled in the left side of the heart, while the right side handles the pulmonary one. </span>
