Which type of cell is analyzed using direct preparation in chorionic villus sampling (CVS)?

Chorionic villus sampling (CVS) involves obtaining a small sample of chorionic villi from the placenta for genetic analysis. The correct choice, cytotrophoblast, refers to the cells that make up the outer layer of the chorionic villi. These cells are essential in the early stages of pregnancy as they play a crucial role in nutrient exchange and contribute to the formation of the placenta.

In CVS, direct preparation focuses on isolating these cytotrophoblast cells because they represent the fetal genome directly. This ability to analyze the cytotrophoblasts allows for the detection of genetic abnormalities early in the pregnancy, making CVS a valuable tool for prenatal diagnosis. Other cell types mentioned, such as fibroblasts, trophoblasts, and amniocytes, do not directly pertain to the chorionic villus sampling process in the same way that cytotrophoblasts do, as they serve different functions in prenatal development and do not yield the same immediate genetic information relevant to CVS.