Difference between Chromosome and Chromatid

Main Difference

These terms are used in DNA study which are often confusing in meaning. The main difference between chromosome and chromatid is, chromosomes are single physical structure and are transmitted through them. But on the contrary, chromosome consists of two identical strand which are called chromatids which are formed during S-phase.


There are 46 chromosomes in every single nucleus of our body. There are 23 chromosomes in pairs and this pairing occurs during the process of meiosis and mitosis. During the process of mitosis, chromosomes are duplicated. It is made up of DNA and protein. DNA present in a chromosome is transferred from parents to their off-spring. Hence, it carries reproductive information which is passed on. In prokaryotes the chromosomes are circular but in eukaryotes they are arranged in a linear pattern. Chromosomes consist of two chromatids which are held at the center by centromere and the structure of chromosome is best studied in meta-phase. Human chromosomes are examined via karyotyping and they are X-shaped, 46 in number. Any abnormality in karyotyping indicated infantile anomaly or any congenital defect. Karyotyping is done before the birth of baby to rule out any such anomaly.


Two chromatids make up a single chromosome. Two chromatids are joined together by a centromere which makes a whole chromosome. When chromatids are separated fro each other during the process of meiosis or mitosis then they are known as sister chromatids and they resemble each other. Chromatids are formed in S-phase and each chromatid is half of chromosome in meta-phase. Chromosomes formed in anaphase form only one chromatid, the reason being splitting of centromere. A chromatid is very important in the process of mitosis as well.

Key Differences

  • Chromosome is a single strand of DNA but two chromatids form one chromosome.
  • Chromosome carry genetic material from parent to off-spring but chromatids do not.
  • Chromatid enable the cell ability to reproduce as compared to chromosome.
  • Chromatids enable the cell to reproduce but chromosome are responsible for giving features, characters and other genetic predispositions.
  • Karyotyping is done in infants, before birth to check the status of child;s chromosomes.
  • Chromosomes are found in different locations of a cell.
  • Chromatid is actually the sister of chromosome.
  • There would be no protein DNA without chromatid, so chromatid is important in that aspect. DNA protein helps in the making of a new cell.
  • Chromatid is the start of the process to create two fully functioning cells.

Video Explanation

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