Turner Syndrome (XO) is the only viable monosomy found in humans. Some sex chromosome trisomies are also viable, including XXX, XXY, and XYY. There are no viable autosomal monosomies, and a small handful of viable autosomal trisomies exist, such as trisomy 21 (Down syndrome), and trisomy 13 and 18, both of which are lethal within the first year of life. Clearly, aneuploidy is not tolerated well in humans. Speculate as to why there are so few viable monosomies (only one) in humans, and why there are so few viable trisomies. Also, speculate as to why aneuploidy involving the sex chromosomes is better tolerated than those involving autosomes.

Question

Turner Syndrome (XO) is the only viable monosomy found in humans. Some sex chromosome trisomies are also viable, including XXX, XXY, and XYY. There are no viable autosomal monosomies, and a small handful of viable autosomal trisomies exist, such as trisomy 21 (Down syndrome), and trisomy 13 and 18, both of which are lethal within the first year of life. Clearly, aneuploidy is not tolerated well in humans. Speculate as to why there are so few viable monosomies (only one) in humans, and why there are so few viable trisomies. Also, speculate as to why aneuploidy involving the sex chromosomes is better tolerated than those involving autosomes.

Quizplus · Accepted Answer

The Answer of Turner Syndrome (XO) is the only viable monosomy found in humans. Some sex chromosome trisomies are also viable, including XXX, XXY, and XYY. There are no viable autosomal monosomies, and a small handful of viable autosomal trisomies exist, such as trisomy 21 (Down syndrome), and trisomy 13 and 18, both of which are lethal within the first year of life. Clearly, aneuploidy is not tolerated well in humans. Speculate as to why there are so few viable monosomies (only one) in humans, and why there are so few viable trisomies. Also, speculate as to why aneuploidy involving the sex chromosomes is better tolerated than those involving autosomes.

Turner Syndrome (XO) Is the Only Viable Monosomy Found in Humans