what are sister and non sister chromatids???????
Sister chromatids: Definition for sister chromatids is, Two identical strands joined by a common centromere as a result of a chromosome that duplicated during the S phase of the cell cycle. Sister chromatids are separated during mitosis so that the two daughter cells would have identical sets of chromosomes.
Non sister chromatids: Definition for non sister chromatids is, Either of the two chromatids of any of the paired (homologous) chromosomes. Non-sister (homologous) chromatids form chiasma(ta) to exchange genetic material during meiosis (i.e. Prophase I).
Sister chromatids : Sister chromatids are two daughter strands of a single replicated chromosome. They are connected by a centromere. The information they carry will be exactly same.
Non sister chromatids : Nonsister chromatids are two daughter strands of homologous chromosomes. The nonsister chromatid will carry the same type of genetic information, but not exactly the same information.
Here is the answer to your question,
� Sister chromatids are identical to each other
� Nonsister chromatids are not identical to each other as they represent different but homologous chromosomes.
� During S phase of the cell cycle the DNA is replicated and an identical copy of the chromatid is made. These two chromatids are then called sister chromatids.
� The non-sister chromatid will carry the same type of genetic information, but not exactly the same information.