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Mendel's Law of independent assortment holds good for genes situated on the
Mendel's Law of independent assortment holds good for genes situated on the
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Solution
The correct option is D non-homologous chromosomes
Each gene comes in two alternating forms called alleles. In eukaryotic cells, DNA is packaged into chromosomes. After the S phase of mitosis, the chromosome contains two chromatids known as sister chromatids joined at the centromere. They contain identical copies of DNA. Thus, the same gene will be present at the same position on both the chromatids. They will contain identical alleles of the gene as their genetic material is identical.
In diploid cells, the chromosomes are present in pairs. One chromosome of each pair is inherited from the father and the other one from the mother. Each pair of chromosomes are known as homologous chromosomes. In case of homologous chromosomes, both the chromosomes will contain the same gene at the same position but the alleles may or may not be identical. The pair of homologous chromosomes segregate during meiosis. Each daughter cell receives only one chromosome from each pair of homologous chromosomes.
Figure: Homologous Chromosomes
When more than one gene is present on the same chromosome, their alleles may or may not segregate independently during meiosis. This is because when the distance between the genes is very less, crossing over during meiosis does not always occur between the two genes. Thus, there is very less chances of exchange of genetic material to occur between the two homologous chromosomes during meiosis. Therefore, mostly parental combinations will be observed in progeny.
Mendel’s Law of independent assortment states that, when two pairs of traits are considered, the segregation of one pair of traits is independent of the other. But if the traits are present on the same chromosome or homologous pairs of chromosomes, their segregation won’t be independent of each other. On the other hand, if the traits are present on non- homologous pairs of chromosomes, their segregation is independent of each other as observed by Mendel in Pisum sativum.
A cell not only contains nucleic acids in the nucleus but also in the cytoplasm. The nucleic acids present in the cytoplasm are called cytoplasmic chromosomes. These do not follow Mendelian inheritance patterns.
Each gene comes in two alternating forms called alleles. In eukaryotic cells, DNA is packaged into chromosomes. After the S phase of mitosis, the chromosome contains two chromatids known as sister chromatids joined at the centromere. They contain identical copies of DNA. Thus, the same gene will be present at the same position on both the chromatids. They will contain identical alleles of the gene as their genetic material is identical.
In diploid cells, the chromosomes are present in pairs. One chromosome of each pair is inherited from the father and the other one from the mother. Each pair of chromosomes are known as homologous chromosomes. In case of homologous chromosomes, both the chromosomes will contain the same gene at the same position but the alleles may or may not be identical. The pair of homologous chromosomes segregate during meiosis. Each daughter cell receives only one chromosome from each pair of homologous chromosomes.
Figure: Homologous ChromosomesWhen more than one gene is present on the same chromosome, their alleles may or may not segregate independently during meiosis. This is because when the distance between the genes is very less, crossing over during meiosis does not always occur between the two genes. Thus, there is very less chances of exchange of genetic material to occur between the two homologous chromosomes during meiosis. Therefore, mostly parental combinations will be observed in progeny.
Mendel’s Law of independent assortment states that, when two pairs of traits are considered, the segregation of one pair of traits is independent of the other. But if the traits are present on the same chromosome or homologous pairs of chromosomes, their segregation won’t be independent of each other. On the other hand, if the traits are present on non- homologous pairs of chromosomes, their segregation is independent of each other as observed by Mendel in Pisum sativum.
A cell not only contains nucleic acids in the nucleus but also in the cytoplasm. The nucleic acids present in the cytoplasm are called cytoplasmic chromosomes. These do not follow Mendelian inheritance patterns.
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