Term
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Definition
| are any segment of DNA that evolves the ability to move from place to place within a genome |
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Term
| MARCUS RHODES AND BARBARA MCCLINTOCK |
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Definition
| inferred existence of TE's from genetic studies of corn |
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Term
| TE's HAVE NOW BEEN FOUND IN ALL ORGANISMS |
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Definition
-previously considered to be selfish DNA-> carried no genetic info
-now known that some have evolved function
-TE length ranges from 50bp - 10kb
-can be present in hundreds of thousands of copies per genome |
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Term
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Definition
| caused by movements of a TE into and out of a pigment gene |
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Term
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Definition
-2 poly A tails-> long and short
-one has long terminal repeats-> human endogenous retroviruses
-her s are similar in structure |
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Term
| EVIDENCE THAT RETROTRANSPOSONS MOVE |
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Definition
Ty1 with intron cloned into plasmids
introns spliced out, for reverse transcriptase to continue |
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Term
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Definition
transcription of retrosposons
synthesis of cDNA by reverse transcriptase
staggered cut made in genomic target site
retroposons insert into target site
original copy remains while new copy inserts into another genomic location |
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Term
| STRUCTURE OF DNA TRANSPOSONS |
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Definition
-most DNA transposons contain->
-inverted repeats (IR) of 10-20 bp long at each end
-gene encoding transposase, which recognizes the IR's and cuts at border btwn the IR and genomic DNA |
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Term
| MANY TE's SUSTAIN DELETIONS DURING THE PROCESS OF |
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Definition
-transposition or after transposition
- deletion of promoter for retro.. transcription
-deletion of reverse transcriptase gene or transposase gene
-deletion of IR's
-most SINE's and LINE's in human genome are defective |
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Term
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Definition
| nondeleted TE's that can transpose on their own |
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Term
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Definition
| defective TE's that can transpose only if transposase activity expressed form intact TE |
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Term
| TE INSERTION CAN RESULT IN ALTERED PHENOTYPE |
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Definition
-TE can insert within coding region of a gene
-TE can insert near a gene and affect its expression |
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Term
| TE's CAN TRIGGER SPONTANEOUS CHROMOSOMAL REARRANGEMENTS |
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Definition
| unequal crossing over between TE's |
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Term
| GENE RELOCATION DUE TO TRANSPOSITION |
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Definition
| formation of composite TE |
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Term
| SPONTANEOUS MUTATIONS IS THE |
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Definition
-white gene of Drosophila arising from TE insertion
-eye color phenotype depends on the TE involved and where it inserts |
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Term
| INSTABILITY OF TE-ASSOCIATED ALLELES |
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Definition
-a nonautonnmous TE inserted into gene C and disrupts its function
- in kernels that have an autonomus TE (AC), DS can hop out restoring gene function |
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Term
| GENE RELOCATION DUE TO TRANSPOSITION |
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Definition
-can occur when 2 copies of a TE integrate in nearby locations on the same chromosome.
-transposase can recognize outermost IR sequences and move intervening sequences to a different location |
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Term
| RELOCATION DUE TO TRANSPOSITION |
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Definition
-can move up to 400 kb of DNA
-mediatees transfer of drug resistance genes between different strains and species of bacteria |
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Term
| ALTERNATIVE SPLICING OF TRANSPOSASES GENE LIMITS TE MOVEMENT |
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Definition
-one splice form produces transposasae
-the other produces a repressor
-the repressor competes with transposase for binding the inverted repeats |
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Term
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Definition
-is the loss or gain of one or more chromosomes.
-individuals whose chromosome number is not an exact multiple of the diploid number (2n) for that species |
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Term
| ANEUPLOIDY USUALLY RESULTS IN MULTIPLE ABNORMALITIES OR LETHALITY |
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Definition
-autosomal monosomy is usually lethal
-most trisomies are lethal, few result in characteristic syndrome
-sex chromosome aneuploidy is tolerated due to x chromosome inactivation |
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Term
| PHENOTYPE OF X-CHROMOSOME |
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Definition
| aneuploidy is largely due to pseudoautosomal genes |
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Term
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Definition
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Term
| ANEUPLOIDY IS CAUSED BY NONDISJUNCTION |
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Definition
| is the failure of chromosomes to segregate normally and can occur during meiosis 1 |
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