Determining Relatedness Between Species Flashcards
What is DNA sequencing?
Determining the exact order of nucleotides in a section of DNA
How is DNA sequencing used to determine relatedness between species?
Sections from 2 organisms similar genes are sequenced and compared, with a number of differences indicative of how related the 2 are.
Why are organisms Mitochondria useful in determining relatedness?
Mitochondria contain their own circular DNA which mutates at a known rate. Only mothers can pass down their mitochondria.
How does the molecular clock work?
As we know the rate at which mitochondrial DNA mutates if we compare 2 organisms mitochondrial DNA the amount of differences/mutations that have accumulated will tell us how long ago the 2 species diverged from one another
How does DNA hybridization determine relatedness between species?
2 samples of DNA are denatured and then mixed and combined together to form a single strand. The strands are then re heated and the temperature at which they denature indicates how many similarities there are in each strands base sequence
What does a high Tm mean?
stronger bonds = less difference between strands = more related
What does a low Tm mean?
Weaker bonds = more difference between strands = less related
What difference in melting temperature corresponds to a one per cent difference in DNA sequence?
1-degree Celsius
What temperature is DNA heated to so the strands separate in DNA hybridization?
87 degrees Celsius
What bonds hold together DNA?
Hydrogen bonds
What does a phylogenetic tree show?
The evolutionary relatedness between species
What is the protein that’s level of production affects the Galapagos finches beak formation?
BMP4
What techniques can be used to make a phylogenetic tree?
Molecular techniques such as DNA sequencing, molecular clocks and hybridisation
