Using the genomic libraries, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.
How frequently will a clone representing myostatin be found in the cDNA library made from muscle?

Verified step by step guidance

1. Understand the concept of a cDNA library: A cDNA library is created by reverse transcribing mRNA from a specific tissue or cell type into complementary DNA (cDNA). This library represents the genes actively expressed in that tissue or cell type.
2. Identify the tissue source: Since myostatin is expressed only in muscle cells, the cDNA library must be made from mRNA extracted from muscle tissue. This ensures that the library contains cDNA corresponding to myostatin.
3. Determine the abundance of myostatin mRNA: The frequency of finding a clone representing myostatin in the cDNA library depends on how abundant the myostatin mRNA is in muscle cells relative to other mRNAs. This can be estimated by analyzing gene expression levels in muscle tissue.
4. Calculate the proportion of myostatin cDNA: Divide the number of myostatin mRNA molecules by the total number of mRNA molecules in muscle cells. This gives the proportion of myostatin cDNA in the library.
5. Estimate the frequency of finding a clone: Multiply the proportion of myostatin cDNA by the total number of clones in the cDNA library. This provides the expected frequency of finding a clone representing myostatin.

Key Concepts

cDNA Library

A cDNA library is a collection of complementary DNA (cDNA) sequences synthesized from messenger RNA (mRNA) transcripts. It represents the expressed genes in a specific tissue or cell type, allowing researchers to study gene expression. In this context, a cDNA library made from muscle cells would contain clones of genes that are actively expressed in muscle tissue, including myostatin.

Gene Cloning

Gene cloning is the process of creating copies of a specific gene or DNA sequence. This involves isolating the gene of interest, inserting it into a vector (like a plasmid), and introducing it into host cells for replication. Cloning the myostatin gene from the cDNA library allows researchers to study its function and regulation in muscle cells.

Expression Frequency

Expression frequency refers to how often a particular gene is expressed in a given tissue or cell type. In the context of the cDNA library from muscle cells, the frequency of myostatin clones will depend on its expression level in those cells. If myostatin is highly expressed, it is more likely to be found frequently in the library, while low expression would result in fewer clones.