Question

Chorionic villus sampling differs from amniocentesis in that for CVS

A. cells must first be cultured.
B. biochemical tests can be performed on the sample.
C. a karyotype is prepared directly from collected cells.
D. cells do not directly descend from the fertilized ovum.

Answer 1

Option (C), Chorionic villus sampling allows a karyotype to be prepared directly from collected placental cells, differentiating it from amniocentesis where cells may need to be cultured first.

Step-by-step explanation:

Chorionic villus sampling (CVS) differs from amniocentesis primarily because in CVS, a karyotype can be prepared directly from the collected cells without the need for culturing them. This is because the cells retrieved during CVS are placental cells that originate directly from the fertilized ovum and are already in a dividing state.

Hence, the option 'C' is accurate, that is, a karyotype is prepared directly from collected cells. In contrast, cells from amniocentesis may need to be cultured before they are in the right state for preparing a karyotype.

Both procedures, CVS and amniocentesis, allow for a range of biochemical tests and genetic analysis of the fetus. CVS can usually be performed earlier in the pregnancy than amniocentesis, offering earlier information about the genetic health of the fetus.