A child is bom with an extra chromosome in each of its cells. This is usually the result of

A. nondisjunction

B. crossing over

C. segregation

D. hybridization

You can do it
  1. When two genes are situated very close to each other in a chromosome
  2. Base substitutions from base analogues I are called
  3. DNA duplication occurs in
  4. Which one of the following chemical characteristics is not common to all living beings ?
  5. Crossing over in meiosis occurs in
  6. The condition in which only one allele of a pair is present is known as
  7. How many meiosis will be required to produce 102 pollen-grains ?
  8. The best method to determine whether an individual is homozygous or heterozygous is
  9. Colour blindness is caused due to
  10. Dyad is
  11. Linked genes may be separated by the process of
  12. The first person to induce mutations was
  13. A codon is a sequence of 3 nucleolides on
  14.  A person meets with an accident and great loss of blood has occurred. There is no time to analyse…
  15. Which disease results from the genetic inability to synthesize a single enzyme ?
  16. A functional unit of a gene which specifies synthesis of one poly-peptide is known as
  17. The chromosomal theroy of heredity implies that
  18. The number of characters investigated by Mendel was
  19. Among the following which is a test cross?
  20. Diakinesis is characterised by
  21. Some people experience PTC paper on tongue as bitter, others as tasteless. This character is hereditary…
  22. The segment of DNA which participates in crossing over is known as
  23.  A chemical mutagen is
  24. Linkage is
  25. The scientists who rediscovered the Mendel's laws are
  26. Mutations which are not dominant are not lost by a gene pooL This is known as
  27. An offspring of two homozygous parents different from one another by alleles at only one gene locus…
  28. The genetic constitution of an organism is known as
  29. Lethal genes are those which
  30. Transfer of a gene or genes through a virus is called