Deletions in Mice in the Hoxa3 Gene,on the a Cluster,result

question 29

Multiple Choice

Deletions in mice in the Hoxa3 gene,on the A cluster,result in abnormal formation of glands in the neck.Deletions in the homologous Hoxd3 gene,on the D cluster,result in abnormal formation of the neck skeleton.The protein-coding sequences of Hoxa3 and Hoxd3 are about 50% the same.Researchers inserted a functional copy of the coding sequence of Hoxd3 in place of the coding sequence of a nonfunctional Hoxa3.They left all promoters,enhancers,splicing signals,and processing signals of Hoxa3 in place.Normal neck gland development was restored.What can you conclude? (J.M.Greer,J.Puetz,K.R.Thomas,and M.R.Capecchi.2000.Maintenance of functional equivalence during paralogous Hox gene evolution.Nature 403:
661-65. )

• A)The protein-coding sequence is most important in producing different functions.
• B)Regulation of the genes is most important in producing different functions.
• C)Either the protein-coding sequence or regulation of the genes is most important in producing different functions.

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Definitions:

Ice Age

A period of long-term reduction in the temperature of the Earth's surface and atmosphere, leading to the expansion of continental and polar ice sheets and alpine glaciers.

Significant Event

An occurrence of notable importance, often changing the course of history or impacting a large area or population.

Type of Isolation

Various forms of separation in biology that prevent species from mating and producing viable offspring, critical in the process of speciation.

Arctic Fox

A small mammal adapted to living in cold climates, known for its thick fur and opportunistic feeding habits.