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प्रश्न
Enlist different types of restriction enzymes commonly used in rDNA technology? Write about their role.
उत्तर
There are three types of restriction enzymes:
- Type I – These enzymes function simultaneously as endonuclease and methylase e.g. EcoK.
- Type II – These enzymes have separate activities for cleaving and methylation; they are more stable and are used in rDNA technology e.g. EcoRI, BglII; these enzymes cut DNA at specific sites within the palindrome. There are thousands of type II restriction enzymes that are recognized/ discovered.
- Type III – These enzymes cut DNA at specific non-palindromic sequences e.g. HpaI, MboII.
Role of restriction enzymes:
Restriction enzymes either cut straight across the DNA in the region of palindrome to give blunt ends or cuts producing short, single-stranded projections at each end of DNA to produce, cohesive or sticky ends or staggered ends.
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OR
What will be the impact if the ori in the above structure gets damaged? - The lac z gene has many recognition sites. Study the segment of DNA given below and answer the questions.
5’... ATC GTA AAG CTT CAT…3’
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