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19 Cards in this Set
- Front
- Back
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what are autosomal chromosomes?
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any chromosomes that aren't sex chromosomes
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which type of disorder can skip generations? autosomal dominant or autosomal recessive?
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autosomal recessive
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why is there no such thing as carriers in a dominant disease?
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even heterozygotes are affected because is a dominant disorder
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how can 2 unaffected parents produce an unaffected offspring?
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either envrionmental trigger
or due to minor modifier genes - incomplete penetrance |
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state what an x-linked trait is and give an example
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mutation that causes it is on the X chromsome
hemophilia |
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why are female identical twins not identical?
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different X chromsomes inactivated
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How is 1 X chromosome inactivated?
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by conversion to heterochromatin - condensed and seen as Barr body
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how is Xist involved in X chromosome inactivation?
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Xist is X inactivation specific RNA transcript that coats X chromosome and prevents transcription of most genes.
It is transcribed from the inactivated X chromosome The Xist coating is associated with silencing gene transcription |
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what is Von Willebrands disease?
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blood clotting disorder classified into Type 1 type 2 and type 3 based on severity.
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what causes VWD?
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mutations in the vWF gene that encodes a factor active in the blood clotting cascade
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what dog breed has the highest prevalence of VWD?
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Doberman
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is type 1 VWD (the most common form) domiant or recessive?
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recessive
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what is the most severe type of VWD?
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type 3
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which dog breeds is type 2 present in?
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german wire-haired and german short-haired pointers
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which dog breeds is type 3 VWD present in?
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scottish terriers, Dutich kooiker, and chesapeake Bay retrievers
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what is the only dog breed where type 3 VWD is reported to be autosomal dominant?
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shetland sheepdogs
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What is the normal 4 step clotting reaction?
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1. vasoconstriction to reduce blood flow
2. platelet plug formation (VWF binds damaged vessel and platelets) 3. activation of clotting cascade with generation of fibrin clot formation 4. fibrinlysis (clot breakdown) |
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What does the ELISA assay for VWDs show? When do problems arise?
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results give amount of factor and diagnosis based on broad range of vWF
<30 units = affected 30-80 units = carrier > 80 units = normal problems if delayed in post or exposed to warm temps |
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Why is it thought that the affected breeds arise from a common ancestor?
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same exon 43 mutation is unlikely to have arisen de novo in 9 different breeds!
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