Microsatellite-assisted backcross selection in maize

A microsatellite marker (SSR) was chosen to simulate a target allele and three criteria (02, 04 and 06 markers per chromosome) were tested to evaluate the most efficient parameters for performing marker-assisted backcross (MAB) selection. We used 53 polymorphic SSRs to genotype 186 BC1 maize (Zea mays L.) plants produced by crossing the inbred maize lines L-08-05 (donor parent) and L-14-4B (recurrent parent). The second backcross (BC2) generation was produced with 180 plants and screened with markers which were not recovered from the first backcross (BC1) generation. A total of 480 plants were evaluated in the third backcross (BC3) generation from which 48 plants were selected for parental genotype recovery. Recurrent genotype recovery averages in three backcross generations were compatible with those expected in BC4 or BC5, indicating genetic gain due to the marker-assisted backcrossing. The target marker (polymorphic microsatellite PHI037) was efficiently transferred. Six markers per chromosome showed a high level of precision for parental estimates at different levels of maize genome saturation and donor alleles were not present in the selected recovered pure lines. Phenotypically, the plants chosen based on this criterion (06 markers per chromosome) were closer to the recurrent parent than any other selected by other criteria (02 or 04 markers per chromosome). This approach allowed the understanding that six microsatellites per chromosome is a more efficient parameter than 02 and 04 markers per chromosome for deriving a marker-assisted backcross (MAB) experiment in three backcross generations

ISPMD consensus on the management of premenstrual disorders

The second consensus meeting of the International Society for Premenstrual Disorders (ISPMD) took place in London during March 2011. The primary goal was to evaluate the published evidence and consider the expert opinions of the ISPMD members to reach a consensus on advice for the management of premenstrual disorders. Gynaecologists, psychiatrists, psychologists and pharmacologists each formally presented the evidence within their area of expertise; this was followed by an in-depth discussion leading to consensus recommendations. This article provides a comprehensive review of the outcomes from the meeting. The group discussed and agreed that careful diagnosis based on the recommendations and classification derived from the first ISPMD consensus conference is essential and should underlie the appropriate management strategy. Options for the management of premenstrual disorders fall under two broad categories, (a) those influencing central nervous activity, particularly the modulation of the neurotransmitter serotonin and (b) those that suppress ovulation. Psychotropic medication, such as selective serotonin reuptake inhibitors, probably acts by dampening the influence of sex steroids on the brain. Oral contraceptives, gonadotropin-releasing hormone agonists, danazol and estradiol all most likely function by ovulation suppression. The role of oophorectomy was also considered in this respect. Alternative therapies are also addressed, with, e.g. cognitive behavioural therapy, calcium supplements and Vitex agnus castus warranting further exploration