Biology - Genetics - Advanced - Sex-linked inheritance - X-Linked Inheritance Explained

5 steps. Step 1: 'SEX CHROMOSOMES: XX = female, XY = male. The X chromosome is large (800+ genes). The Y chromosome is tiny (50 genes). Most X-linked genes have NO equivalent on Y.' Step 2: 'X-LINKED RECESSIVE (most common): If a male has one recessive allele on his X (Xᵇ Y), he SHOWS the trait beca