BIO 325 Lecture 16: Lecture 16
Lecture 16
What The Genome Sequence Is Good For
• Identify genes
o Gene – a gene is a sequence of DNA that encodes a protein or a non-coding RNA
o DNA –> mRNA –> Protein
• Compare genes in the genome
• Examine the structure of our genome
• Compare our genome to other organisms
• Examine the relationship between gene expression on a genomic scale
Identifying Genes
• Comparison to expressed sequence tag (EST) database
o Sequence cDNA libraries
o One sequencing run per clone
o No sequencing of the entire cDNA
o No non-coding RNA found
o EST Sequences
▪ Each EST sequence aligns to the genomic DNA that encodes the mRNA
▪ Limitation: no non-coding RNAs, cDNA libraries only contain genes that
are expressed in the tissue type used to create the library, rare messages
• Gene prediction progras coputatioal predictio
o Programs that scan the genome looking for genes
o Look for
▪ Open reading frames
▪ Stop codon: TAG, TGA, TAA (43 = 64/3 = 1/ 21 codons
• Comparisons to other organisms
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
If a sequence is not important (not a gene), its sequence will not be conversed between organisms. If a sequence is important (encodes a gene), its sequence is more likely to be conserved. Important force in evolution of new genes: contigs sequence contigs is the final contiguous sequence each overlapping read is arranged into. Genome evolution: synteny (cid:272)onser(cid:448)ed gene order (cid:271)et(cid:449)een spe(cid:272)ies is (cid:272)alled (cid:862)synteny(cid:863) or blocks of colinearity genes on 2 different species, human and mouse chromosome. Northern blot (rna: northern blot electrophoresis of (cid:862)rna(cid:863) through gel, tra(cid:374)sfer of rna to solid support usi(cid:374)g (cid:862)(cid:374)ylo(cid:374) or (cid:374)itrocellulose(cid:863) Intensity of hybridization signal: equal to amount of rna, standard technique for assaying gene expression, downside can only check 1 gene at a time. Southern blot (dna: southern blot electrophoresi(cid:374)g of (cid:862)dna(cid:863) through gel, transfer of dna to solid support usi(cid:374)g (cid:862)(cid:374)ylo(cid:374) or (cid:374)itrocellulose(cid:863)
