Woolly mammoths have been extinct for about 10,000 years, but we often find their well- preserved remains in Siberian permafrost. Research groups are now planning to use SCNT to resurrect these huge elephant- like mammals. No mammoth eggs have been recovered so far, so elephant eggs would be used instead. An elephant would also be the surrogate mother for the resulting embryo. The researchers may try a modified SCNT technique used to clone a mouse that had been dead and frozen for sixteen years. Ice crystals that form during freezing break up cell membranes, so cells from the frozen mouse were in bad shape. Their DNA was transferred into donor mouse eggs, and cells from the resulting embryos were fused with mouse stem cells. Four healthy clones were born from the hybrid embryos. What are some of the pros and cons of cloning an extinct animal?

You are studying a new gene “X” that you think controls skin color in Bearded Dragons. In order to determine what gene X does you need lots of gene X DNA to work with. So, you decide to amplify it through the process known as PCR. You have a forward and a reverse primer that have been designed to gene Xf – a gene in frogs that is similar to the one found in the Bearded Dragon. You are pretty sure that these two primers will work in Bearded Dragons, so you decide to go ahead with the PCR. In frogs, the Forward Xf primer binds gene Xf between nucleotides 32 and 47. The Reverse Xf primer binds between nucleotides 1110 and 1135.  What size PCR product would these two primers create if they amplified the frog gene Xf??  bp

In the experiment summarized below, scientists were examining the presence of specific sequences in individuals with age. In this experiment they extracted DNA from lymphocytes of various aged individuals and measured the length of a TTAGGG (in kb) repeat they found in their genomic DNA (Left Panel). In the right panel, the scientists measured the length of the same repeats in individuals with lymphocyte failure (red dots most severely effected) that have a mutation in a critical enzyme. Answer the following questions in 2-3 sentences each. A. What is the name of the specific sequence the scientists are measuring in the experiment shown below. B. For the individuals with lymphocyte pathology in the right panel, which gene is likely defective that causes the data shown? C. Explain why the length of the repeat sequence decreases with age.

What are some of the technical challenges of cloning a mammoth?  Check all that are true   Ancient mammoth DNA has degraded so it is hard to know the complete genome sequence   Mammoth gestation time is likely too short to allowing cloning   A living surrogate mother would have to be used, which could pose problems since the closest relative to mammoths is endangered elephants   A living oocyte would have to be obtained from an extant species, which could pose problems since the closest relative to mammoths is endangered elephants   Mammoths lived so long ago that they used a different genetic code than modern animals   There are no enzymes in existence that could ligate together mammoth DNA sequence with elephant sequence   Mammoths probably had egg shells, which would be hard to penetrate with a needle