AFLP analysis of genetic diversity within and among Coffea arabica cultivars.

Genetic diversity of Coffea arabica cultivars was estimated using amplified fragment length polymorphism (AFLP) markers. Sixty one Coffea accessions composed of six arabica cultivars, including Typica, Bourbon, Catimor, Catuai, Caturra and Mokka Hybrid, plus two diploid Coffea species, were analyzed with six EcoRI- MseI primer combinations. A total of 274 informative AFLP markers were generated and scored as binary data. These data were analyzed using cluster methods in the software package NTSYSpc. The differences among cultivars at the DNA level were small, with an average genetic similarity of 0.933. Most accessions within a cultivar formed a cluster, although deviant samples occurred in five of the six cultivars examined due to residual heterozygosity from ancestral materials. Among the six cultivars fingerprinted, the highest level of genetic diversity was found within the cultivar Catimor, with an average genetic similarity of 0.880. The lowest level was found within Caturra accessions, with an average genetic similarity of 0.993. Diversity between C. arabica and two other Coffea species, Coffea canephora and Coffea liberica, was also estimated with average genetic similarities of 0.540 and 0.413, respectively, suggesting that C. canephora is more closely related to C. arabica than is C. liberica. The genetic variation among arabica cultivars was similar to the variation within cultivars, and no cultivar-specific DNA marker was detected. Although arabica cultivars appear to have a narrow genetic base, our results show that sufficient polymorphism can be found among some arabica cultivars with a genetic similarity as low as 0.767 for genetic/QTL mapping and breeding. The assessment of genetic diversity among arabica cultivars provided the necessary information to estimate the potential for using marker-assisted breeding for coffee improvement.

Are estrogen assays essential for monitoring gonadotropin stimulant therapy?

Ovarian responses to human menopausal gonadotropin (hMG) are conventionally monitored by urinary estrogen or serum estradiol (E2) concentration. E2 can also be measured in saliva but this is rarely used. With ultrasound (USS) however, follicular development is assessed directly and we have previously shown that USS is superior to urinary estrogens for monitoring. We have now compared salivary and serum E2 with USS during hMG therapy in 48 women over 101 cycles. Salivary and serum E2 correlated significantly with each other and with the number of mature follicles. The manufacturers of hMG state that hCG should be given only when E2 is between 100 and 3000 pmol/l. However, there were no mature follicles in 40% of the cycles where E2 lay within this range. USS is the most accurate method of monitoring responses to hMG and, where this is available, estrogen assay provides no additional useful information.

Development of a radioimmunoassay for measuring gonadotrophin releasing hormone in patients receiving treatment.

A radioimmunoassay for the measurement of gonadotrophin releasing hormone (GnRH) in plasma and urine using readily available reagents was developed. The GnRH assay showed good precision, recovery, and parallelism over a wide range of GnRH concentrations with a sensitivity of 15 pg/ml. The assay was compared with a commercially available kit (Buhlmann Laboratories). Although the Buhlmann kit showed acceptable precision, recovery, sensitivity, and correlation with the developed GnRH assay for plasma samples, lack of parallelism of serially diluted plasma and urine samples was consistently observed, together with a poor correlation with the developed GnRH assay for urine, suggesting a matrix effect with the Buhlmann kit. The developed assay is suitable for measuring GnRH in samples obtained from patients receiving pulsatile infusions of GnRH. In contrast, the commercially available Buhlmann kit was unsuitable for measuring plasma GnRH as the kit had a top standard of only 160 pg/ml, well below the peak plasma concentration. It would not be possible to dilute samples for analysis because of the lack of parallelism of diluted samples compared with standards obtained with the Buhlmann assay.