Main difference – Homologous Chromosomes vs sister Chromatids

Most organisms have actually DNA together their genetic material. Diploid organisms together as human beings bear two copies of comparable chromosomes. This are recognized as homologous chromosomes. Throughout metaphase ns of meiosis I, homologous chromosomes appear in pairs. Sister chromatids room the two exact duplicates which are developed by the replication of one DNA molecule in ~ the S phase of the interphase. The key difference between homologous chromosomes and sister chromatids is the homologous chromosomes may not bring identical information all the time whereas sister chromatids lug identical details all the time.

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Key areas Covered

1. What are Homologous Chromosomes – Definition, Characteristics 2. What room Sister Chromatids – Definition, Characteristics 3. What is the Difference between Homologous Chromosomes and Sister Chromatids – compare of key Differences


What space Homologous Chromosomes

Homologous chromosomes are the chromosomes pairing in metaphase ns of meiosis. One chromosome in the pair bear maternal origin while the various other chromosome bear the paternal origin. One chromosome of the homologous pair is described as a homologue. Chromosome length and their positions of the centromeres are the very same within the pair. Every copy includes an appropriate number of same genes, arranged in the same order (same loci). Hence, banding pattern of every chromosome in the pair appears the same. However, the exact same locus might contain either the very same allele or a different allele on both chromosomes. Thus, one individual might be homozygous or heterozygous because that a specific character. Humans have 22 homologous pairs of autosomes and also 2 sex chromosomes . Female sex chromosomes, X and X space homologous while masculine sex chromosomes, X and Y space not important homologous. X and also Y differ from your size and genetic composition. The pairing that homologous chromosomes allows random segregation of hereditary material. Homologous chromosomes exchange your DNA through recombination. Recombination at sexual reproduction leader to hereditary variations in the offspring which in turn facilitates the evolution. Homologous chromosomes separate during anaphase i of meiosis I. 4 haploid daughter cells are produced at the finish of the meiosis. Chromosomal abnormalities such together trisomy and monosomy have the right to occur due to the nondisjunction of homologous chromosomes.


Figure 1: Homologous Chromosomes

What space Sister Chromatids

Sister chromatids space two the same chromatids resulting in DNA replication during the S step of interphase. They are joined with each other by the centromere. A sister chromatid is a one-half of a replicated chromosome. Hence, every replicated chromosome is written of 2 sister chromatids. Sisters chromatids are similar to every other; among them is the specific replica of the other. The exemption is crossing over at prophase i of meiosis I. Chromosomal crossover exchanges genetic material over homologous chromosomes. Sister chromatids separate from each other during anaphase the mitosis and the anaphase II of meiosis II.


Figure 2: sisters Chromatids

Difference between Homologous Chromosomes and also Sister Chromatids


Homologous Chromosomes: Homologous chromosomes are comprised of both maternal and also paternal chromosomes.

Sister Chromatids: sister chromatids are comprised of either a maternal or head chromosome.

Genetic Composition

Homologous Chromosomes: Homologous chromosomes might contain very same or various alleles of the same gene. Thus, the gene sequence is not identical at all the times.

Sister Chromatids: sister chromatids contain identical gene succession throughout the chromatids other than in the chromosomal crossover.


Homologous Chromosomes: Homologous chromosomes appear in the metaphase ns of meiosis I.

Sister Chromatids: sister chromatids space formed during the DNA replication in the S step of interphase.


Homologous Chromosomes: Homologous chromosomes execute not pole together. Lock exist in pairs.

Sister Chromatids: sisters chromatids room joined together by your centromere.

Number that DNA Strands

Homologous Chromosomes: Homologous chromosomes space composed of 4 DNA strands.

Sister Chromatids: single sister chromatid is created of a single DNA strand.


Homologous Chromosomes: Homologous chromosomes are segregated during the anaphase ns of meiosis I.

Sister Chromatids: sisters chromatids are separated from your centromere during anaphase II the meiosis II and the anaphase the mitosis.


Homologous Chromosomes: Homologous chromosomes permit random segregation of chromosomes and also genetic recombination throughout metaphase I.

Sister Chromatids: sister chromatids enable random segregation of chromatids and chromosomal crossover throughout metaphase II the meiosis and metaphase the mitosis.

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Homologous chromosomes are composed the both maternal and paternal chromosomes. Therefore, various alleles the the exact same gene deserve to be discovered most the the times. On the various other hand, sister chromatids space composed of very same allele of a gene in both strands because they room synthesized by the DNA replication the a strand. Thus, the key difference in between homologous chromosomes and sister chromatids is in their hereditary composition.

Reference: 1. “Homologous Chromosomes”. Pearson – The biological Place. Accessed 12 Feb. 2017 2. “Homologous chromosome”. Wikipedia, the free encyclopedia. 2017, Accessed 12 Feb. 2017 3. Mccarthy E. M. “Sister chromatids”. Virtual Biology Dictionary. Accessed 17 Feb. 2017

Image Courtesy: 1. “PloSBiol3.5.Fig7ChromosomesAluFish.”. Through Bolzer et al., (2005) Three-Dimentional Maps the all person Male Fibroblast Nuclei and Prometaphase Rossttes. PloS Biol 3(5): e157 DOI: 10.1371/journal.pbio.0030157, number 7a (CC-BY-2.5) via Commons Wikimedia 2. “HR in meiosis”. Through Emw – Own work-related (CC-BY-SA-3.0) via Commons Wikimedia