An Approximate Procedure for Determining Prediction Error Variances of Sire Evaluations

Prediction errors of sire evaluations can be obtained directly from the inverse of the appropriate coefficient matrix. Considerably more effort is required to obtain the inverse in practical situations than can be justified for publication of a confidence figure. An approximate prediction error variance, k/(n + 20), is used currently in the Northeast Artificial Insemination Sire Comparison where n is the number of daughters and k is an appropriate breed constant corresponding to the residual variance. This procedure, however, does not account for distribution of sires across herds nor several lactations per daughter. Thus, the diagonal elements of the sire equations after absorption of cow, sire-by-herd, natural service sire, and herd-year-season equations were chosen as likely indicators of the prediction error variance for this more complicated model. Simple regression was used to relate prediction error variance obtained from the inverse to the diagonal after absorption. The coefficient of determination was .995 or greater in all cases. A single approximate prediction error variance of sire evaluation (group plus sire solution) could be used for Ayrshire, Guernsey, Jersey, and Brown Swiss bulls (and probably for Holsteins, which were not studied). The approximate prediction error variance is [-.0014 + 1.08/diagonal] times the appropriate residual variance. An approximation comparable to repeatability for herdmate comparisons also was derived as [1.01 - 9/diagonal]

The spindle position checkpoint is coordinated by the Elm1 kinase

Localization and activation of Elm1 at the bud neck coordinates SPC activity with mother–daughter polarity during cell division

Elm1 kinase activates the spindle position checkpoint kinase Kin4

Elm1 phosphorylates a conserved residue within the Kin4 kinase domain to coordinate spindle position with cell cycle progression

Budding Yeast Dma Proteins Control Septin Dynamics and the Spindle Position Checkpoint by Promoting the Recruitment of the Elm1 Kinase to the Bud Neck

The first step towards cytokinesis in budding yeast is the assembly of a septin ring at the future site of bud emergence. Integrity of this ring is crucial for cytokinesis, proper spindle positioning, and the spindle position checkpoint (SPOC). This checkpoint delays mitotic exit and cytokinesis as long as the anaphase spindle does not properly align with the division axis. SPOC signalling requires the Kin4 protein kinase and the Kin4-regulating Elm1 kinase, which also controls septin dynamics. Here, we show that the two redundant ubiquitin-ligases Dma1 and Dma2 control septin dynamics and the SPOC by promoting the efficient recruitment of Elm1 to the bud neck. Indeed, dma1 dma2 mutant cells show reduced levels of Elm1 at the bud neck and Elm1-dependent activation of Kin4. Artificial recruitment of Elm1 to the bud neck of the same cells is sufficient to re-establish a normal septin ring, proper spindle positioning, and a proficient SPOC response in dma1 dma2 cells. Altogether, our data indicate that septin dynamics and SPOC function are intimately linked and support the idea that integrity of the bud neck is crucial for SPOC signalling

Stabilność temperaturowa wyciskanego hydrostatycznie aluminium

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