Chapter 15 Flashcards
DNA
Species that are more closely related gave similar DNA than those which are distantly related
Universal nature of genetic code and has a biochemical nature.
DNA codes everything, mainly proteins.
Genome
Complete set of DNA of an organism.
Endogenous retroviruses
Viral sequence that has become part of an organisms genome.
The more ERV’s they have in common, the more common ancestors they have.
ERV’s are an example of Junk DNA (does nothing).
Junk DNA
Sections of DNA that don’t code for a particular characteristic.
More similarities in Junk DNA = closer ancestor.
Mitochondrial DNA
Occurs in the mitochondria.
Only can get it from your mum - because part of the sperm is left behind when it reaches the egg.
The fast mutation rate means it’s more useful for the relationships between species (tracking heritage).
- used to rack migratory patterns, relationships between species and verifying evidence for evolution.
Protein studies
Less similarities = less identical amino acid sequences.
There’s less differences between proteins than DNA - because protein is doing something.
Proteins have an amino acid sequence.
Suggests a common ancestor.
Ubiquitous proteins
Every organism contains them.
Everyone from a simple bacterium to a complex multicellular organism use cytochrome-C for cellular respiration to create ATP, this tells us that we have originated from a common ancestor.
Bioinformatics
Using computer software to map and compare genomes.
What we use to interpret DNA and proteins.
Measures changes in different species DNA rather than their physical taxonomy.
Comparative genomes
Comparing complete genomes, showing differences and similarities.
Comparative embryology
Comparing the very early stages of development of vertebrate organisms - suggests all vertebrates share a common ancestor.
Early embryos of all species have: gill arches, gill pouches, tails, no limbs, two chambered hearts and similar brain development.
Homologous structures
Organs that have similar in structure but they perform different actions and functions - this suggests they have a common ancestor.
For example, forelimb bones are homologous organs (whales and humans).
Vestigial organs
Structures of reduced size that appear to have no function.
Two examples:
Verminform appendix - useful for when we were mostly vegetarian (grass) - now we eat more meat.
Coccyx - left over tail (ancient ancestor had a tail).
Geographical distribution
Isolated land areas and islands have evolved their own distinct plant and animal population.
E.g. Finches in Galapagos Islands off South America -> gradual change/evolution of beak shapes to increase survival -> speciation (changing or evolving so differently they can no longer interbreed).
How do retroviruses become endogenous?
If it’s inserted into a sex cell, it can be passed down.
Biotechnology for DNA comparison
- PCR amplifies (makes more) DNA.
2. DNA is sequenced by gel electrophoresis and bacterial enzymes.
