History at your fingertips. One homologous chromosome is inherited from the organism's mother; the other is inherited from the organism's father. Second, scientists began to notice differences between the behavior of chromosomes only recently observed during mitosis and meiosis.
The X chromosome resembles a large autosomal chromosome with a long and a short arm. The Z-W system occurs in some birds, insects, and fish Fig 6. Help Community portal Recent changes Upload file.
Traits controlled by genes found only on the X chromosome are said to be sex-linked see linkage group. This study demonstrated that the gene for eye color in D. In humans the sex chromosomes consist of one pair of the total of 23 pairs of chromosomes. The sister chromatids in the two daughter cells are pulled apart during anaphase II by nuclear spindle fibers, resulting in four haploid daughter cells.
Sister chromatids result after DNA replication has occurred, and thus are identical, side-by-side duplicates of each other. There are two important facts to remember about sex chromosomes. Cell Biology 2 ed.
Wikimedia Commons. Homologous chromosomes can repair this damage by aligning themselves with chromosomes of the same genetic sequence. This problem is a part of the Human Genetics Problem Set. Morgan Figure 3 of Columbia University first mapped a gene to a specific chromosome.