Your question is flawed. A clone is a genetically identical copy of another organism. It has nothing to do with reasoning or intelligence. If you clone a sheep, as they did in the 1900's, the intellegence of the sheep is equivalent to the sheep from with it was cloned from. If you clone a human, the intellegence of that human will be indentical to the human from whom he/she was cloned from.
However, if you are referring to biotechnology and genetic engineering then yes. Remember, down's syndrome is caused by a mutation in a single human gene. Intellegence isn't unique. We arn't able yet to alter our DNA, but we are making progress. Damaged or Cancerous cells can be replaced with healthy cells and through viruses, we are able to manipulate any DNA because DNA is universal which is why the DNA from one organism can be transported to another