Difference in Plumage Color Used in Species Recognition between Incipient Species Is Linked to a Single Amino Acid Substitution in the Melanocortin‐1 Receptor

This is the publisher's version, also available electronically from http://www.jstor.org/stable/10.1086/600084Many studies demonstrate that differences in mating signals are used by incipient species in recognizing potential mates or sexual competitors (i.e., species recognition). Little is known, however, about the genetic changes responsible for these differences in mating signals. Populations of the Monarcha castaneiventris flycatcher vary in plumage color across the Solomon Islands, with a subspecies on Makira Island having chestnut bellies and blue‐black upper parts (Monarcha castaneiventris megarhynchus) and a subspecies on neighboring satellite islands being entirely blue‐black (melanic; Monarcha castaneiventris ugiensis). Here we show that a single nonsynonymous point mutation in the melanocortin‐1 receptor (MC1R) gene is present in all melanic birds from one island (Santa Ana) but absent in all chestnut‐bellied birds from Makira Island, implicating this mutation in causing melanism. Birds from a second satellite island (Ugi) do not show the same perfect association between this MC1R variant and plumage color, suggesting an alternative mechanism for melanism on this island. Finally, taxidermic mount presentation experiments in Makira (chestnut) and Santa Ana (melanic) suggest that the plumage difference mediates species recognition. Assuming that the signals used in species recognition are also used in mutual mate choice, our results indicate that a single amino acid substitution contributes to speciation

Legal Opinion Letters and Texas Usury Laws.

Abstract Forthcoming

The GAP activity of Msb3p and Msb4p for the Rab GTPase Sec4p is required for efficient exocytosis and actin organization

Polarized growth in Saccharomyces cerevisiae is thought to occur by the transport of post-Golgi vesicles along actin cables to the daughter cell, and the subsequent fusion of the vesicles with the plasma membrane. Previously, we have shown that Msb3p and Msb4p genetically interact with Cdc42p and display a GTPase-activating protein (GAP) activity toward a number of Rab GTPases in vitro. We show here that Msb3p and Msb4p regulate exocytosis by functioning as GAPs for Sec4p in vivo. Cells lacking the GAP activity of Msb3p and Msb4p displayed secretory defects, including the accumulation of vesicles of 80–100 nm in diameter. Interestingly, the GAP activity of Msb3p and Msb4p was also required for efficient polarization of the actin patches and for the suppression of the actin-organization defects in cdc42 mutants. Using a strain defective in polarized secretion and actin-patch organization, we showed that a change in actin-patch organization could be a consequence of the fusion of mistargeted vesicles with the plasma membrane

CYP2C19 genetic polymorphisms in Maltese patients on clopidogrel therapy

Introduction and Aims: The prevalence of CYP2C19 genetic polymorphisms in the Maltese population is not reported. The aims were to determine CYP2C19 *2 and *17 allele frequencies and CYP2C19 genotype distribution in a cohort of Maltese patients on clopidogrel and to compare observed frequencies of the CYP2C19 *2 allele and *2/*2 genotype to other populations bordering the Mediterranean Sea. Methods: Genotyping for the CYP2C19 *2 and *17 alleles in Maltese patients on clopidogrel was performed using TaqMan® drug metabolism assays. The frequency of both alleles and six genotypes (*1/*1, *1/*2, *2/*2, *1/*17, *17/*17, *2/*17) were determined. Observed frequencies of the CYP2C19 *2 allele and *2/*2 genotype were compared to fourteen populations bordering the Mediterranean Sea (p>0.05 indicated similar prevalence) Results: Frequencies of the CYP2C19 *2 and *17 alleles in the 244 patients genotyped were 12.3% and 15.4% respectively. CYP2C19 genotype distribution was: *1/*1 (52.1%), *1/*17 (22.5%), *1/*2 (18.0%), 2/*17 (6.6%), *17/*17 (0.8%) and *2/*2 (0). Prevalence of the *2 allele in the Maltese cohort was similar to all fourteen populations bordering the Mediterranean Sea, while prevalence of *2/*2 was similar to Egyptian, Moroccan, Southern French, Slovenian, Turkish and Tunisian populations (p>0.05). Conclusions: This study provides an indication of the prevalence of CYP2C19 polymorphisms in Maltese patients. The high percentage of patients with CYP2C19 IM or UM phenotype demonstrates that CYP2C19 genotyping could aid clinicians to individualise treatment with clopidogrel and other drugs metabolised by the CYP2C19 enzyme.peer-reviewe