F1 hybrid progenies between related subspecies often show hybrid sterility (HS) or inviability. HS is caused by failure of meiotic chromosome synapsis and sex body formation in house mouse. Previous studies identified two HS critical genomic regions named Hstx2 on chr X and Hst1 on Chr 17 by murine forward genetic approaches. HS gene on Hst1 was reported to be Prdm9. Intersubspecific polymorphisms of Prdm9 induce HS in hybrids, and Prdm9 null mutation leads to sterility in the inbred strain. However, HS gene on Hstx2 remains unknown. Here, using knockout studies, we showed that HS candidate genes on Hstx2 are not individually essential for spermatogenesis in B6 strain. We examined 12 genes on Hstx2: Ctag2,

No abstract

In tennis, the service is the only shot that a player can give himself without being influenced by his opponent, and it is said to be the most powerful and essential shot in the game to win the game (Kovacs and Ellenbecker, 2011). In this study, we will investigate the difference in speed and spin rate in services when a service is entered, when it is not entered, and when an ace is taken. Fourteen three-set singles matches of 20 participants in the ATP Challenger tournament were included in the analysis. The speed and spin rate was measured using the Trackman. The analysis included 1343 1st service balls. We compared the speed and spin rate for each IN, FAULT and ACE in the 1st service using one-way ANOVA. The speed of the 1st service, IN was significantly slower than that of FAULT and ACE. The spin rate of the 1st serve, IN had significantly more revolutions than the FAULT and ACE. The results of this study showed that the service was faster and lower spin rate when ACE was taken. However, it was found that the faster the speed of the service and the lower the spin rate, the higher the rate of FAULT. These considerations suggest that it is important to decide whether to take risks or play it safe, depending on the game situation at the time.

No abstract