Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example Input: Context: Coming off their divisional home win over the Cardinals, the 49ers flew to the Edward Jones Dome for a Week 2 divisional duel against their NFC West rival, the St. Louis Rams. In the first quarter, the Niners trailed early as Rams QB Marc Bulger completed a 12-yard TD pass to WR Torry Holt for the only score of the period. In the second quarter, San Francisco would tie the game up with RB Frank Gore getting a 1-yard TD run. St. Louis would take the halftime lead with kicker Jeff Wilkins getting a 29-yard field goal In the third quarter, the 49ers took the lead with Gore breaking through a gang of tacklers for a 43-yard TD run, along with the only score of the period. In the fourth quarter, the Rams retook the lead with Wiklins getting a 53-yard field goal. Fortunately, thanks to a St. Louis goof-up on special teams, the Niners took the lead with kicker Joe Nedney getting a 40-yard field goal. Near the end the game, the Rams had one last chance to win the game. Fortunately for San Francisco, Wilkins' 56-yard field goal attempt fell about a yard short of the crossbar. With the win, the 49ers improved to 2-0 for the first time since 1998. Q1 - STL - 6:04 - 12-yard TD pass from Marc Bulger to Torry Holt (Wilkins kick) (STL 7-0) Q2 - SF - 14:57 - Frank Gore 1-yard TD run (Nedney kick) (7-7) Q2 - STL - 9:04 - Jeff Wilkins 27-yard FG (STL 10-7) Q2 - STL - 1:51 - Jeff Wilkins 29-yard FG (STL 13-7) Q3 - SF - 2:43 - Frank Gore 43-yard TD run (Nedney kick) (SF 14-13) Q4 - STL - 10:04 - Jeff Wilkins 53-yard FG (STL 16-14) Q4 - SF - 3:23 - Joe Nedney 40-yard FG (SF 17-16) 
 Question: How did the 49ers take the lead in the fourth quarter?
Example Output: joe nedney

Example Input: Context: The authors describe a family with six patients with muscular dystrophy with a variable course. One is a compound heterozygote for CAPN3 mutations (calpainopathy) and the others have a single CAPN3 mutation. Linkage analysis and sequencing revealed a XK gene mutation (McLeod syndrome). This illustrates the variable phenotype of XK mutations and suggests the possibility that CAPN3 heterozygotes may have their condition caused by nonallelic mutations in other unrelated genes. 
 Question: Mutation of which gene is associated with McLeod syndrome?
Example Output: xk

Example Input: Context: The expression of selenoproteins requires the translational recoding of the UGA stop codon to selenocysteine. In eukaryotes, this requires an RNA stem loop structure in the 3'-untranslated region, termed a selenocysteine insertion sequence (SECIS), and SECIS-binding protein 2 (SBP2). This study implicates SBP2 in dictating the hierarchy of selenoprotein expression, because it is the first to show that SBP2 distinguishes between SECIS elements in vitro. Using RNA electrophoretic mobility shift assays, we demonstrate that a naturally occurring mutation in SBP2, which correlates with abnormal thyroid hormone function in humans, lies within a novel, bipartite RNA-binding domain. This mutation alters the RNA binding affinity of SBP2 such that it no longer stably interacts with a subset of SECIS elements. Assays performed under competitive conditions to mimic intracellular conditions suggest that the differential affinity of SBP2 for various SECIS elements will determine the expression pattern of the selenoproteome. We hypothesize that the selective loss of a subset of selenoproteins, including some involved in thyroid hormone homeostasis, is responsible for the abnormal thyroid hormone metabolism previously observed in the affected individuals. 
 Question: What is the name of the stem loop present in the 3' end of genes encoding for selenoproteins?
Example Output:
secis