AP BIOLOGY

Detailed explanation-1: -In humans, the alleles for certain conditions (including some forms of color blindness, hemophilia, and muscular dystrophy) are X-linked. These diseases are much more common in men than they are in women due to their X-linked inheritance pattern.

Detailed explanation-2: -Sex linkage applies to genes that are located on the sex chromosomes. These genes are considered sex-linked because their expression and inheritance patterns differ between males and females. While sex linkage is not the same as genetic linkage, sex-linked genes can be genetically linked (see bottom of page).

Detailed explanation-3: -Sex-linked genes are located on the X chromosome result in X-linkage. Similarly, Y-linkage refers to the gene which is present on the Y chromosome. Since females are homogametic with XX chromosome and males have XY chromosome, the Y-linked traits are transmitted via males only.

Detailed explanation-4: -Sex-linked diseases are inherited through one of the sex chromosomes, which are the X and Y chromosomes. Dominant inheritance occurs when an abnormal gene from one parent can cause a disease, even though a matching gene from the other parent is normal.