In a transformation experiment donor DNA from an a b strain

In a transformation experiment, donor DNA from an a^+ b^+ strain was used to transform a recipient strain of genotype a b. The transformed classes were isolated and their frequencies determined to be a^+ b^+ 307 a^+ b 215 a b^+ 278 The total number of transformants was 800. What is the frequency with which the b locus is cotransformed with the a locus? What is another name for a bacterial virus?

Solution

7. Gene transfer in bacteria takes place by three methods; transformation, transduction and conjugation.

Transformation involves uptake of genetic material from the surrounding medium and its incorporation into bacterial chromosome and plasmids.

Transformants – Cells that receive genetic material through transformation.

Genes can be mapped by looking at the rate at which two or more genes are cotransformed in transformation.

High cotransformation frequency indicates a shorter distance between two genes on the donor chromosome.

In the Transformation experiment :-

Donor strain is a⁺b⁺

Recepient strain is ab

a⁺b⁺       307

a⁺b       215

ab⁺       278

Total number of transformants = 800

Frequency with with b locus is cotransformed with a locus ;

Cotransformation Frequency = number of transformed cells with a⁺b⁺ genotype / total number of transformed cells

= 307 / 800

= .38 or 38.37% is the cotransformation frequency.

8. The another name of bacterial virus is bacteriophage.