In a family father is affected by down syndrome and mother is normal then what will be percentage of affected offspring
Answers
50%
as the father will produce sperms, in which 50% would be normal and other 50% would be having the homlogous chromosomes attached leading to down's syndrome if they fertilize an egg
Answer:
Most of the time, Down syndrome isn't inherited. It's caused by a mistake in cell division during early development of the fetus. ... When balanced translocations are inherited, the mother or father has some rearranged genetic material from chromosome 21 on another chromosome, but no extra genetic material.
Explanation:
Normally, at the time of conception a baby inherits genetic information from its parents in the form of 46 chromosomes: 23 from the mother and 23 from the father. In most cases of Down syndrome, a child gets an extra chromosome 21 — for a total of 47 chromosomes instead of 46. It's this extra genetic material that causes the physical features and developmental delays associated with DS.
Although no one knows for sure why DS happens and there's no way to prevent the chromosomal error that causes it, scientists do know that women age 35 and older have a significantly higher risk of having a child with the condition. At age 30, for example, a woman has about a 1 in 1,000 chance of conceiving a child with DS. Those odds increase to about 1 in 400 by age 35. By 40 the risk rises to about 1 in 100.