Term
| Population transcriptomics is |
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Definition
| The use of high-throughput methods that quantify gene expression levels (such as microarrays or RNA-seq) to determine levels of gene expression variation among individuals of a species |
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Term
What are the causes of expression
differences? |
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Definition
1) Changes over time/development
2) Environment
3) Sex |
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Term
| In males, there is less expression polymorphism on the X chromosome than on the autosomes. This pattern is not seen in females. Why? |
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Definition
| male-biased genes show the greatest expression polymorphism, but are significantly under-represented on the X chromosome. Since male-biased genes are mainly expressed in males and show very high expression polymorphism among males, their relative absence from the X leads to it having less expression polymorphism among females. |
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Term
| Factors explaining less expression polymorphism among females than among males |
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Definition
1) Genetic polymorphism on the Y chromosome has a large effect on the expression of autosomal and X-linked genes (no Y in females).
2) Genetic polymorphism in the mitochondrial genome has a large affect on male, but not female, gene expression (mit from mother)
3) there is greater purifying selection to maintain an optimal expression level in females than in males |
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Term
| Where is more expression differences between populations of flyes? |
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Definition
| in females. Most environmental adaptation at the level of gene expression occurs in a sex-specific manner. |
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Term
| What if the expression divergence of a gene is the result of adaptive cis-regulatory evolution? |
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Definition
1) DNA sequence polymorphism should be reduced in at least one of the populations,
producing “selective sweep”
2)There should be one or more fixed (or nearly fixed) sequence differences between the populations. |
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Term
| How to test cis-regulatory evolution? |
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Definition
| A “reporter gene”, in which upstream region from either of alleles is placed in front of the E. coli lacZ gene.The reporter genes can then be inserted into a precise location of the D.melanogaster genome using a method known as PhiC31 site -specific integration. |
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Term
| Difference in brain expression |
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Definition
there were more expression differences in the brain between populations than between sexes and most genes that differed in expression between populations showed the
same pattern in both sexes.An example is MtnA, which is involved in heavy metal detoxification: positive selection in Europe. |
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