Genetic linkage ,Mapping & crossing over

crossing over is the exchange of segment between homologous chromosomes

 

just as in diagram it is represented that fragment x has homologous chromosome

that is cr,Band other Y has ++.when it is cross over it then produce parental genotype

and as well as recombinant that is cr + and +B.they are cross over

EVIDENCES OF CROSS-OVER

Direct evidence was firstly given in  1931 by c.stern working on drosophila

stern studied two x chromosomes that differed from the normal x chromosomes.that one chromosome has y chromosome on its one end and 2nd ha smaller than normal chromosomes.

Two linked gene eye color( car) and shape is bar like and cross over occur in these just as in diagram on top.

Gene mapping

DNA Replication in prokaryotes

As i figure its show that in prokaryotes replicaton majore requirements is

Helicase

SSB

Polymerases

Okazaki fregments

POLYMEASES 

Their are several type of polymerases in prokaryotes that are
Plymerase 1
Polymerase 2
Polymerase 3

polymerase 1; it is the repair enzyme that fill the gap in between newley synthesised DNA

polymerase 2' its function is still unkown but its consider to be helpfull to polymease 3

polymerase 3: it is the replicating enzyme

PROTEINS:

Helicase;
that is the most important for sepration of DNA stands.its seprate DNA strand.
SSB:
its also protein that prevents to rewinding of DNA strands

ENZYMES:

REPLISOMES
it consist if replicating units
two Beta clamps

Anatomy of man

In human's body organ's are placed in an arrangrd manner if anything is distubed then man faced 

many problems in the form of dieses,which leads to death.

The most important organ of our body is liver.

in case of infection in liver many diseases occur such  Hepatitis that is most common in Pakistan or in many other countries like india, which is mostly occurs due to the infection in liver.

now many types of hepatitis can be seen

such as; Hepatitis A 

or Hepatius B, C,D,E