Junk DNA (2/21) Flashcards
What is different in organisms?
- ) Sequence of bases along DNA strand
- ) Amount of genetic material
- ) # of genes and chromosomes
Is the number of chromosomal pairs a reliable predictor for organism complexity?
No
How many base pairs (haploid) are in a human genome?
about 6.4 million bases = 2 x 3.2 million base pairs
Is the number of BP’s a reliable predictor for organism complexity?
No
Is the number of protein-coding genes a reliable predictor for organism complexity?
Nope
What percent of our DNA codes for proteins?
1.5% (98.5% of our genome is non-coding)
What are Introns?
“Junk DNA”
- much of the RNA transcribed from junk DNA plays a central role in regulating the activity of protein-coding genes and proteins
- JUNK DNA ISNT JUNK!
What percentage of our DNA comes from viruses?
- 3% comes from “fossil” virus DNA, aka “retrotransposons”
- these viruses infected our ancestors and their genetic material has been passed along to us
Do you think viruses meet all the criteria typically used to define a living organism?
No! They cannot reproduce themselves!
Where do we think viruses originally came from?
They may have evolved from plasmids (pieces of DNA that can move between cells)
Is there a correlation between the amount of non-coding “junk” DNA and organismal complexity?
Yes, but we are just starting to understand how our non-coding DNA contributes to our complexity
What is “Gene Regulation”?
any mechanism used by a cell to increase or decrease the production of a specific gene product (proteins or RNA)
What codes for Micro-RNA (miRNA)?
miRNA is a non-coding RNA present in all living organisms, found on tangled strips of DNA
What does Micro-RNA do?
prevents RNA from translating into proteins
When does “RNA Interface” occur?
translation from RNA proteins
- the interception of transcription products can strongly affect the phenotype without any modification of the genotype