Question

Commonly used vectors for human genome sequencing are
a. T-DNA
b. BAC and YAC
c. Expression vectors
d. T/A cloning vectors

Answer 1

Hint: Normally used vectors for human genome sequencing are BAC as in Bacterial Artificial Chromosome as well as YAC. The BAC is a DNA construct, based on a functional fertility plasmid known as F plasmid which is used for transforming as well as cloning in bacteria. Yeast artificial chromosomes YACs are genetically engineered chromosomes obtained from the DNA of the yeast, Saccharomyces cerevisiae, which is then ligated into a bacterial plasmid.

Complete answer:
> T-DNA
The transfer DNA or known as abbreviated T-DNA is the transferred DNA of the tumor-inducing plasmid of some specific species of bacteria like Agrobacterium tumefaciens as well as Agrobacterium rhizogenes.

> BAC and YAC
The term YAC stands for yeast artificial chromosome and the term BAC stands for bacterial artificial chromosomes. These are the two vectors which are basic tools to insert the gene of interest in the host cell. The key difference between these two vectors is that of the insert size of the gene of interest. YAC can accommodate a bigger size of gene of interest than BAC.

> Expression Vector
An expression vector, also known as an expression construct, is mainly a plasmid or virus designed for gene expression in cells. The vector is used to introduce a specific gene into an interest cell, as well as can commandeer the cell's mechanism for protein synthesis in order to produce the protein encoded by the gene.

> T/A cloning
TA cloning also called rapid cloning or T cloning is a sub cloning method that avoids the use of restriction enzymes as well as it is easier and quicker than traditional sub cloning.

Hence, the correct answer is option (B).

Note: By inserting large fragments of DNA, from about 100–1000 kb, the target sequences can be cloned as well as physically mapped using a process known as chromosome walking. This process was initially used for the Human Genome Project. But because of the stability issues, YACs were abandoned for the use of Bacterial artificial chromosomes that are BAC.