Final answer:
Individuals with sex chromosome aneuplodies, like trisomy or monosomy, often have a higher survival rate due to the mild effects facilitated by X inactivation, allowing survival and development into adulthood despite certain challenges.
Step-by-step explanation:
The likelihood of survival for individuals with sex chromosome aneuploidy, such as trisomy or monosomy, is generally higher than for those with autosomal aneuploidies. Sex chromosome anomalies tend to have milder effects due to the process of X inactivation, which occurs early in the development of female mammalian embryos. Females naturally carry two X chromosomes, but one of these becomes a Barr body, a dormant structure that ensures only one X chromosome is active in each cell, preventing a double genetic dose.
This process balances the gene expression from X chromosomes and allows for a relatively normal development despite an abnormal number of sex chromosomes. Therefore, individuals with conditions such as Turner syndrome (monosomy X) or Klinefelter syndrome (trisomy XXY) can survive and live into adulthood, albeit with some physical, reproductive, and/or cognitive challenges.