Question

Inbreeding for five generations led to production of homozygous transgenic mice. However, these homozygous males or females were infertile. Which of the following approaches is most preferable and economical to obtain heterozygous transgenic animals continuously?

• A. More transgenic founder (1st animal) should be generated.
• B. Crossing (breeding) of transgenic mice with wild type mice in earlier generations should be done for continued production of transgenic heterozygous offsprings
• C. Inbreeding should be avoided after 5th generation
• D. Homozygous transgenic mice should be mated with heterozygous transgenic mice for continued production of transgenic heterozygous offsprings.

Answer 1

The correct option is B Crossing (breeding) of transgenic mice with wild type mice in earlier generations should be done for continued production of transgenic heterozygous offsprings

Interbreeding of particular species for a larger amount of time causes the recessive traits to appear in the offspring and those result in infertility. Inbreeding is not recommended and cross-breeding is required. When the transgenic mice are inbred for very large duration infertility is caused.

To get heterozygous transgenic mice crossbreeding should be done with the wild-type.

So, the correct option is 'Crossing (breeding) of transgenic mice with wild type mice in earlier generations should be done for continued production of transgenic heterozygous offsprings'