Difference Between Sister Chromatids and Non-Sister Chromatids

Main Difference

The main difference between sister chromatids and non-sister chromatid is that sister chromatid discusses the identical copies form by the DNA replication of a chromosome when both copies join together by a common centromere whereas non-sister chromatid refers to either one of the two chromatids of pair homologous chromosomes.

Sister Chromatids vs. Non-Sister Chromatids

Sister chromatids are the two same copies of a chromatid having the same genes and alleles whereas non-sister chromatid contains two strands as one is inheriting from its mother while the other one is inheriting from its father. Replicating chromosome contains two sister chromatids, which are connecting by the centromere while non-sister chromatids are the two chromatids from two different homologous chromosomes. Sister chromatids are identical to each other as they are producing by DNA replication, but non-sister chromatids are non-identical as non-sister chromatid is inheriting from each parent. Sister chromatids are producing in the S phase of the interphase, but in the metaphase, I of meiosis non-sister chromatids are producing. Sister chromatids comprise the same alleles at the same loci conversely non-sister chromatids comprises alters alleles of same genes at the same loci. Sister chromatids are present on the same chromosome whereas non-sister chromatids are present in a homologous chromosome pair. Sister chromatids are involving in asexual reproduction; on the other hand, non-sister chromatids are involving in sexual reproduction.

Comparison chart

Sister ChromatidNon-Sister Chromatid
Two chromatids of replicated chromosomes which are connected by a centromereTwo chromatids from two different homologous chromosomes
Identity
Identical to each other and produce by DNA replicationNon-identical since the two are inheriting from each parent
Alleles
Contain the same allele at the same lociContain different allele of the same gene at the same loci
Formation
Form in the S phase of the interphaseForm during the metaphase I of meiosis
Found In
Found on the same chromosomesFound in the homologous chromosomes
Participation
Participate in asexual reproductionParticipate in sexual reproduction

What is Sister Chromatid?

The two chromatids of a replicating chromosome are connecting by the centromere are refer as sister chromatids. Sister chromatid is ‘one-half’ of the duplicating chromosome. One pair of sister chromatids is known as a dyad. A full set of sister chromatids is forming during the synthesis of the S phase of interphase after all the chromosomes in a cell are replicating. The two sister chromatids are separating from each other into two different cells during mitosis or during the second division of meiosis. In some species, sister chromatids are the desiring template for DNA repairing. Sister chromatid consistency is essential for the correct distribution of genetic information between daughter cells and repairing the damage in chromosomes. Each pair of sister chromatids contains the same allele at the same loci. During the metaphase of mitosis, replicating chromosomes make parallel at the cell equator. After that in anaphase, sister chromatids are separating from each other and move towards the opposite poles. Through metaphase, I of meiosis, homologous chromosomes pair at the cells equator and sister chromatids remains the same during anaphase I. Individual replicating chromosomes arrange at the cell equator in metaphase II. The parting of sister chromatids occurs at anaphase II. Finally, each sex cell comprises a single sister chromatid from each chromosome. Faults in this process may lead to aneuploidy and cancer, mainly when checkpoints flop to identify DNA damage or when imperfectly attach mitotic spindles don’t function properly.

What is Non-Sister Chromatid?

The chromatids in alter chromosomes of a homologous chromosome pair are referring as non-sister chromatids. Non-sister chromatids are also known as homologous. Both chromosomes of non-sister chromatid contain different alleles of the same gene at the same loci. Homologous chromosome pairs take the same staining pattern, same length, centromere position as well as the same characters of genes at particular loci. Each homologous chromosome is inheriting from each parent. One non-sister chromatid is inheriting from its mother while the other one is inheriting from its father. A non-sister chromatid is not identical. Non-sister chromatids are creating during meiotic cellular division. All chromosome with a diploid chromosome number in the genome consists of another non-sister chromatid. These two non-sister chromatid pair during the metaphase I of meiosis. When homologous chromosomes pair with each other, chromosomal crossover can occur between non-sister chromatids of each pair. Crossing over occurs from chiasmata during prophase I of meiosis. The process is called homologous recombination. When the gametes unite, each chromosome in the pair contains the biological features due to non-sister chromatid of the parent such as the color of the hair, eyes, and skin. Homologous recombination is one of the causes of genetic variation among individuals within the same population. A child can inherit any characteristics of his parents because each pair in the chromosomes carries his parents’ traits. There are 22 pairs of non-sister chromatids known as autosomes and one pair of sex chromosomes.

Key Differences

  1. Sister chromatids are the two chromatids of a replicating chromosome, which are connecting by the centromere while non-sister chromatids are two chromatids from two different homologous chromosomes.
  2. Sister chromatids are identical to each other as they are producing by DNA replication, but non-sister chromatid is inheriting from each parent, as non-sister chromatids are non-identical.
  3. Sister chromatids are producing in the S phase of the interphase on the flip side non-sister chromatids are forming in the metaphase of meiosis.
  4. Sister chromatids comprise the same alleles at the same loci conversely non-sister chromatids contain different alleles of same genes at the same loci.
  5. Sister chromatids are present on the same chromosome whereas non-sister chromatids are present in a homologous chromosome pair.
  6. Sister chromatids are involving in asexual reproduction; on the other hand, non-sister chromatids are involving in sexual reproduction.

Conclusion

Above this discussion, it concludes that sister chromatids and non-sister chromatids are the results of DNA replication. Sister chromatids are the two chromatids that initiate from the same chromosome. Nonsister chromatids contain different alleles at each locus as their origination is different.

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