The following experiment is designed to study the role of several hormones in the regulation of metamorphosis in frogs.

Group #	Treatment	Days to Metamorphosis
1	Saline	30
2	Prolactin	> 100
3	TSH	15
4	Thyroxine	10
5	Corticosterone	30
6	Thyroxine + Corticosterone	5
7	Prolactin + TSH	30
8	Thyroid gland removed	> 100

 If the thyroid gland were removed from the tadpoles in Group 3, metamorphosis would

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#Question id: 16137

#Unit 13. Methods in Biology

You obtain 6 BACs (of known order, as shown below) and 7 STSs (of unknown order) that derive from a region of mouse chromosome 16 whose genomic sequence has not yet been finished.   

 

By PCR (using 20-bp primers at either end of each STS), you test each of the 6 BACs for the presence (+) or absence (-) of each of the 7 STSs. You obtain the following results:

 

How would you use the sequence information presented in to design two new STSs (with new PCR primer pairs) to replace STS5? (Call the new ones STS51 and STS52. STS51 should be present (+) in BAC B, and STS52 should be present (+) in BAC F.)

TLS Online TPP Program

#Question id: 16138

#Unit 13. Methods in Biology

You obtain 6 BACs (of known order, as shown below) and 7 STSs (of unknown order) that derive from a region of mouse chromosome 16 whose genomic sequence has not yet been finished.   

 

By PCR (using 20-bp primers at either end of each STS), you test each of the 6 BACs for the presence (+) or absence (-) of each of the 7 STSs. You obtain the following results:

 

Would you expect STS51 and STS52 to be present in BAC D? 

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#Question id: 16139

#Unit 13. Methods in Biology

 Many mouse genes are “tissue-specific,” that is, they are present throughout the body but are expressed in only one of the animal’s many tissue types. (Other mouse genes are expressed throughout the body, or in multiple tissues.) Geneticists can study the regulation of a mouse gene by fusing the gene’s promoter region to the LacZ coding sequence and injecting the construct to create a transgenic mouse. Fusion of the mouse amylase promoter to LacZ yielded a Pamylase-LacZ construct.              

Mice heterozygous for the resulting Pamylase-LacZ  transgene displayed the LacZ expression exclusively in the pancreas. Would you expect homozygotes for the transgene to also display LacZ expression in the pancreas?.

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#Question id: 16140

#Unit 13. Methods in Biology

Many mouse genes are “tissue-specific,” that is, they are present throughout the body but are expressed in only one of the animal’s many tissue types. (Other mouse genes are expressed throughout the body, or in multiple tissues.) Geneticists can study the regulation of a mouse gene by fusing the gene’s promoter region to the LacZ coding sequence and injecting the construct to create a transgenic mouse. Fusion of the mouse amylase promoter to LacZ yielded a Pamylase-LacZ construct.

You are surprised to observe that mice homozygous for the transgene insertion display a serious heart defect. (Heterozygotes have normal hearts.) which one is a  possible explanation?

a) LacZ overexpression (with two copies of the transgene) causes the defect.

b) the insertion disrupted a gene that is haploinsufficient.

c) the insertion disrupted a gene that is haplosufficient.

d) LacZ expression inhibition (with two copies of the transgene) causes the defect.

Which of the following statements is correct  predict about the  heart defect?

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#Question id: 17270

#Unit 13. Methods in Biology

which of the following are the three important components of Electrophoresis 

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#Question id: 17271

#Unit 13. Methods in Biology

Electrophoretic resolution can be mainly change by changing the