A woman with 47 chromosome due to three copies of chromosome 21 is characterized by

Q. A woman with 47 chromosome due to three copies of chromosome 21 is characterized by

Q. A woman with 47 chromosome due to presence of additional 21 chromosome is characterized by

Q. Three copies of chromosome 21 in a child with Downs syndrome have been analysed using molecular biology technology to detect any possible DNA polymorphism with reference to different alleles located on chromosome - 21. Results showed that out of three copies two of the chromosomes of the child contain the same alleles as one of the mother's alleles. Based on this when did the non-disjunction event most likely occur?

Q.

Question 20
The two versions of a trait (character) which are brought in by the male and female gametes are situated on

(a) copies of the same chromosome
(b) two different chromosomes
(c) sex chromosomes
(d) any chromosome

Q. Name the chromosomal disorder which is caused by the presence of an additional copy of the chromosome number 21.