Post a paragraph answering the statement in bold below.  You will be able to see other students’ posts and comment on them after you post yours.  The following questions are only prompts to get you thinking, you do not need to specifically answer the questions below the bold statement in your response.

Describe how you think the number of species and the sizes of their genomes in an environment will affect the sequencing of a metagenome.

For example, think about an environment with 2 different bacterial species where the species are equally abundant and have the same genome size.  During shotgun sequencing, the genomic DNA is sheered and fragments from both genomes are randomly sequenced.  What is the likelihood of sampling a fragment from species A? or species B?

Now think about if the two species are equally abundant, but the genome of species A is 10 Mb and species B is 1 mb.  Now what is the likelihood of sequencing a fragment from species A or species B?

Lastly, imagine the genomes are equal size again, but species A is present in the environment is 10 time the amount of cells as species B.  Now what is the likelihood of sequencing a fragment from species A or B?

How does species abundance and relative genome size affect coverage of the genomes in a metagenome after shotgun sequencing.  Then think about an environment with not just two species, but hundreds, all with different abundance and different genome sizes.