The short, curved leg trait, chrondrodysplasia, is a major cause of dwarfism in

ID: 57978 • Letter: T

Question

The short, curved leg trait, chrondrodysplasia, is a major cause of dwarfism in humans, and it is

caused by inappropriate over-expression of the [____] FGF4 that leads to premature calcification of the

growth plates in long bones of the legs. A recent finding shows that in several common, short-legged dog

breeds such as the dachshund, Welsh corgi, and basset hound, this chrondrodysplasia is caused by a fgf4

[____] that is derived from a spliced and processed mRNA of the source FGFR wild type gene. This

indicates that an RNA-based [____] captured the fgf4 mRNA, [____] the sequence, and inserted the

fgf4 gene into the dog genome, where its over-expression is driven by a [____] from a nearby

retrotransposon. This [____] of a growth factor gene is thought to cause down-regulation or

inactivation of a receptor for the growth factor, and thus suppression of bone growth.

(1) growth hormone; transposon; long interspersed nuclear element; copied; enhancer; under-expression

(2) hormone receptor; gene; retrovirus; reverse-transcribed; regulatory element; gain

(3) growth factor; retrogene; retrotransposon; reverse-transcribed; promoter; over-expression

(4) long interspersed nuclear element; retrotransposon; retrovirus; copied; gene regulator; rearrangement

(5) transposon; gene; retrotransposon; replicated; promoter; loss

Answer:

(3) growth factor; retrogene; retrotransposon; reverse-transcribed; promoter; over-expression

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