The Death of a Gene

When a gene is duplicated, the new copy is often dead-on arrival (lacks the regulatory elements). 

TLS Online TPP Program

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#Unit 2. Cellular Organization

Supercoiling is related to two properties of genome

1. Packaging 

2. Linking number

TLS Online TPP Program

#Id: 369

#Unit 2. Cellular Organization

DNA Packaging or genome packaging is expressed in terms of Packaging Ratio=Original size/packed size  

TLS Online TPP Program

#Id: 370

#Unit 2. Cellular Organization

Linking number is topological property which is expressed as  Total No. of Base Pair/Base pair per turn.

TLS Online TPP Program

#Id: 371

#Unit 2. Cellular Organization

How to calculate linking number?

TLS Online TPP Program

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#Unit 2. Cellular Organization

If Lk <Lk0 and DLk is <0 means negative, then the DNA is said to be “negatively supercoiled.”

TLS Online TPP Program

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#Unit 2. Cellular Organization

Conversely, if Lk >Lk0  and DLk >0 means positive, then the DNA is “positively supercoiled.”