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प्रश्न
Describe the structure of sex-chromosomes.
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उत्तर
Structure of X and Y chromosomes
- X chromosomes are longer than Y chromosomes.
- X chromosome contains large amount of euchromatin and small amount of
heterochromatin, whereas the Y chromosome contains small amount of euchromatin
and large amount of heterochromatin. - Non-homologous region of X-chromosome contains more genes than that of nonhomologous region of Y chromosome.
- Non-homologous region of X-chromosome contains X-linked genes while nonhomologous region of Y chromosome contains Y-linked genes.
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संबंधित प्रश्न
If centromere is situated in the middle of the chromosome, it is called ________.
(a) Metacentric
(b) Acrocentric
(c) Submetacentric
(d) Telocentric
Briefly mention the contribution of T. H. Morgan in genetics.
Answer the following question.
Compare in any three ways the chromosomal theory of inheritance as proposed by Sutton and Bovery with that of experimental results on pea plant presented by Mendel.
A B B C C D E F G H I
From the above figure identify the type of mutation and explain it.
Write the salient features of the Sutton and Boveri concept.
From the following identify the statements that are CORRECT with respect to homologous and non-homologous region of X and Y chromosomes.
i. Non-homologous region of X chromosome is longer and contains more genes than that of non-homologous region of Y chromosome.
ii. X-linked genes are present on nonhomologous region of X-chromosome.
iii. Y-linked genes are present on homologous region of Y-chromosome.
iv. Crossing over occurs only between homologous regions of X and Y chromosomes.
Two or more independent genes present on different chromosomes which determine nearly same phenotype are called ______.
Mendel’s work was rediscovered by three scientists in the year ______.
Chromosomal theory of inheritance was given by ______.
Which of the following statements indicates parallelism in genes and chromosomes?
- They occur in pairs.
- They segregate during gamete formation.
- They show linkage.
- Independent pairs segregate independently.
