Term
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Definition
o genome is broken up into a set of overlapping fragments that are small enough to be sequenced
• using regions of the overlap, sequenced fragments then put back into correct order
• begins by using high-frequency sound waves to break genome into pieces about 160,000 bases long
• each piece inserted into BAC
• each BAC inserted into a different E. coli cell, creating a BAC library
• once have many copies of 160-kb fragment, broken again into 1 kb
• each piece inserted into plasmids and place inside bacterial cells
• computers analyze regions where ends overlap
• overlap occurs b/c many copies of each 160-kb segment and each fragmented randomly by sonification
• goal: arranged each 160-kb segment in its correct position along chromosome, based on regions of overlap |
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Term
| bacterial artificial chromosome (BAC) |
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Definition
| plasmid that is able to replicated large segments of DNA |
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Term
| in bacteria, long stretch of codons that lack a stop codon is good indication of _______ |
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Definition
| coding sequence b/c randomly get a stop codon about every 20 codons |
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Term
| eukaryotic is more complicated b/c |
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Definition
• coding regions broken up by introns
• vast majority of eukaryotic DNA doesn’t actually code for a product |
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Term
o in bacteria, there is a general correlation between the size of a genome and the metabolic capabilities of the organisms
• for example, most parasites have much smaller genomes than nonparasitic organisms |
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Definition
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Term
| about 15% of genes in each species’ genome are ______ |
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Definition
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Term
| two general criteria to support hypothesis that sequences in bacteria or archaeal genomes originated in another species |
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Definition
o when stretches of DNA are much more similar to genes in distantly related species than to those in closely related species
o when proportion of G-C base pairs to A-T base pairs in a particular gene or series of genes is markedly different from base composition of rest of genome |
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Term
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Definition
o movement of DNA from one species to another
• hypothesize it also occurs via transformation – when bacteria and archaea take up raw pieces of DNA from environment, perhaps in course of acquiring other molecules
• can also be transported by viruses
• shows that mutation and genetic recombination are not only source of bacterial genetic variation |
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Term
| many of the repeated sequences in eukaryotes are ___________ |
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Definition
| derived from transposable elements |
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Term
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Definition
o segments of DNA that are capable of moving from one location to another, or transposing, in a genome
• similar to viruses, except that viruses leave a host cell that they have infected and find a new cell to infect
• these never leave their host cell – simple make copies of themselves and move to new locations in genome
• are passed from parents to offspring b/c part of genome
• example of selfish gene
• genomic parasite |
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Term
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Definition
| DNA sequence that survives and reproduces but does not increase the fitness of the host genome |
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Term
| long interspersed nuclear element (LINE) |
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Definition
selfish gene found in eukaryotes
• similar to retroviruses |
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Term
| transposable elements and viruses considered parasites b/c _________ |
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Definition
| takes time and resources to copy them along with rest of the genome and b/c can disrupt a gene function when they move and insert in a new location, decreasing host fitness |
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