Genomes and Their Evolution Flashcards
Eukaryotic genomes tend to be ____ compared to genomes of bacteria and archaea
Larger
Most plants and animal have genomes greater than ____ Mb while humans have ___ Mb
100 ; 3000
What is repetitive DNA?
Present in multiple copies in the genome
What are transposable elements?
Stretches of DNA that can move from one location to another within the genome
About ___ of human repetitive DNA is made up of transposable elements
75%
How do transposons move?
By means of a DNA intermediate and require a transposase enzyme
How do retrotransposons move
By means of an RNA intermediate using a reverse transcriptase
Insertions of transposable elements within a protein-coding sequence may ___ protein production
Block
What are Alu elements?
DNA sequences that can transpose to new locations in a cell’s genome
What is LINE-1 (L1)?
Retrotransposon that produce an RNA intermediate
What is simple sequence DNA?
Many copies of tandemly repeated short sequences
What is a short tandem repeat (STR)?
A series of repeating units of 2 to 5 nucleotides
The basis of change at the genomic level is ____, which underlies much of genome evolution
Mutation
What is polyploidy?
Accidents in meiosis leading to one or more extra sets of chromosomes
What is an example of rearrangements of chromosome structure?
Humans have 23 pairs of chromosomes while chimpanzees have 24, and following divergence of humans and chimpanzees from a common ancestor, two ancestral chromosomes fused in the human line
