L23: What does human genome tell us about being human?

• Things in common are called conserved and may encode biology in common between species
• things that are different may encode organism specific biology
• by comparing genomes we can find out differences such as disease, characteristics of an individual and evolutionary history.
• we can sequence a human genome for $600
• we can compare sequences by lining them up next to each other and marking each point where sequences are the same. this is called 'aligning'
• by comparing genome species, we can identify specific genes present in an organism and evolutionary relationships
• DNA from dead things can remain in the environment and degrades and is masked by more modern DNA
• DNA bases are modified as they degrade and sometimes changing the sequence.
• Ancient DNA can be extracted and identified in very special circumstances. it has been used to determine the relationships of extinct animals
• comparing genomes to an extinct human genome comes with limitations and challenges
• the neanderthals are the closest relative to humans . there are 4 billion neanderthal nucleotides that are identified and discount modern contaimination
• scientists have gathered 3 sequence from 2 individuals, which is enough to compare to the modern human
• some of us carry neanderthal DNA. modern humans from europe and asia carry neanderthal dna. those from africa show no signs of these alleles. this is because neanderthals interbred
• neanderthal DNA adds to variation in our genome that might be related to our phenotype