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Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance5 Marks
Question
Enumerate the salient features of human genome.
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Answer

Salient features of Human Genome:
  1. The human genome contains 3164.7 million nucleotides (base pairs).
  2. The size of the genes varies; an average gene consits of 3000 bases, while the largest gene, dystrophin consists of 2.4 million bases.
  3. The total number of genes is estimated to be 30000 and 99.9% of the nucleotides are the same in all humans.
  4. The functions of over 50% of the discovered genes are not known
  5. Only less than 2% of the genome codes for proteins.
  6. Repetitive segments make up a large portion of the human genome.
  7. Repetitive sequences throw light on chromosome structure and dynamics and evolution, though they are thought to have no direct coding functions.
  8. Chromosome 1 has 2968 genes and Y-chromosome has the least number (231 genes).
  9. Scientists have identified about 1.4 million locations, where DNA differs in single base in human beings; these are called single nucleotide polymorphisms (SNPs).

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