Essentials of Genetics 9th Edition by Michael Palladino William Klug, Michael Cummings, Charlotte Spencer

Exercise 1

Art inspires learning
A genetics student visiting a museum saw a painting by Goya showing a woman with a newborn baby in her lap that had very short arms and legs along with some facial abnormalities. Wondering whether this condition might be a genetic disorder, the student went online, learning that the baby might have Roberts syndrome (RBS), a rare autosomal recessive trait. She read that cells in RBS have mitotic errors, including the premature separation of centromeres and other heterochromatic regions of homologs in metaphase instead of anaphase. As a result, metaphase chromosomes have a rigid, or "railroad track" appearance. RBS has been shown to be caused by mutant alleles of the ESCO2 gene, which functions during cell division.
The student wrote a list of questions to investigate in an attempt to better understand this condition. How would you answer these questions?
What do centromeres and other heterochromatic regions have in common that might cause this appearance?