Eukaryotic Genomes and Mobile Elements

This lecture explores various causes of genetic mutations beyond DNA polymerase errors, focusing on the insertion of mobile genetic elements and their evolutionary impact. It discusses how these elements can disrupt gene function, contribute to genome size, and lead to the development of introns. The lecture also compares genome sizes across different organisms, highlighting the role of genetic parasites in genome expansion. Finally, it examines how mobile elements can alter protein production by affecting gene sequences.

What is a major cause of mutations besides DNA polymerase errors?

• Chromosome duplication

• Mobile genetic elements

• Environmental factors

• Protein synthesis errors

How do mobile genetic elements typically affect a gene when they insert into it?

• They enhance the gene's function

• They have no effect on the gene

• They disrupt the gene's coding sequence

• They duplicate the gene

What is one evolutionary consequence of mobile element insertions?

• Elimination of introns

• Reduction in genome size

• Accumulation of genetic parasites

• Increase in the number of genes

What is thought to be the original cause of introns?

• Mutations in protein-coding genes

• Insertions of a specific type of genetic parasite

• Errors in DNA replication

• Natural selection

Which organisms have very compact genomes with little 'junk' DNA?

• Eukaryotes

• Viruses

• Plants

• Bacteria and Archaea

How do eukaryotic genomes differ from those of viruses and bacteria?

• They have fewer genes

• They have a wider range of genome sizes

• They contain only protein-coding genes

• They are smaller in size

What is the typical number of genes in the human genome?

• About 100,000

• About 50,000

• About 20,000 to 30,000

• About 10,000

What happens to a gene's function when a mobile element inserts into it?

• The gene is duplicated

• The gene becomes more efficient

• The gene's function is usually eliminated

• The gene's function is enhanced

What can mobile elements carry that affects gene regulation?

• Chromosome rearrangements

• Additional coding sequences

• Regulatory signals

• Extra introns

What is a potential outcome when a mobile element carries its own regulatory signals?

• The gene is deleted

• The gene becomes non-functional

• The gene is expressed differently

• The gene is unaffected