"You either have XX or XY chromosomes," Rep. Nancy Mace, R-S.C., wrote Feb. 20 on X. "Those are the options." Most commonly, a person is born with two X chromosomes (female) or an X and a Y (male).

The improper segregation of chromosomes during cell division leads to abnormalities that disrupt the proper functioning of ...

Larger chromosomes contain a higher number of A-T or G-C base pairs, leading to higher levels of Hoechst and chromomycin staining, respectively. As illustrated in Figure 1, chromosome 21 ...