Taylor's experiments on root tips of Vicia faba

The 20th century was the era of genetics

We got to know various things about ‘Genes’.

Genes make us what we are.

We got to know various things about ‘Genes’.

They transfer from one generation to other with some changes in them.

Herbert Taylor in 1958 along with his co-workers explained how a gene is carried to the next generation

They conducted an experiment on the roots of plant

To show how our DNA replicates.

We shall learn about his experiment step by step

The roots of the plant were grown on a medium which has radioactive thymidine in it.

This helps to incorporate radioactivity in the DNA of roots.

After some time, these roots were observed in photographic film.

And the radioactive thymidine appeared on photographic film, confirming the incorporation of radioactivity on them

Let us see the observation under unlabelled medium

Now they transferred the roots with labelled chromosomes to an unlabelled medium containing colchicine.

They observed that in the first generation, the radioactivity was distributed uniformly in chromatids

In second-generation one of two chromatids were radioactive.

This proves that the DNA replicated with the semi-conservative method

This experiment proved that…...

The strands of parent DNA are template for the new daughter strand.

On which only one new daughter strand form.

And this is the reason the replication of DNA is known as semi-conservative as it has one old and one new strand.

Revision

Taylor in 1958 conducted an experiment on

In which he grew the roots of the plant in a medium which has radioactive thymidine

After growing the radioactive DNA in an unlabelled medium he found all chromatids are radioactive in the first generation.

In second-generation one in two chromatids were radioactive.

This is known as semiconservative replication as one older strand and one newly synthesized strands are present.

The End