Search

Within the UK there is an increase in the request for information about an individual''s ancestory. UK population databases are not uncommon but the detailed origin of samples has not traditionally been collected. Typically samples are classified using very general identifiers such as ‘black British’. We have conducted a study to establish whether this lack of detailed information proves to be a major problem when considering population studies relying on SNP data. A panel of Y-chromosome and autosomal SNPs have been used to genotype individuals from a ‘black British’ population and from six Mozambique population groups. The resulting population data sets were contrasted and differences between a well-defined and a broadly characterized population set were used to illustrate the importance of good sample information. A comparison of the different SNP typing methodologies used throughout this study was conducted and all methods were found to work well. [Copyright &y& Elsevier]

This experiment was conducted to test a hypothesis that lactating dairy cows fed 35% brown midrib (BMR) corn silage and 25% alfalfa hay (dry matter (DM) basis) would consume more DM around peak lactation compared with those fed conventional corn silage (CS), resulting in longer peak milk production. Twenty-eight multiparous Holstein cows were used starting at the onset of lactation through 180 d in milk (DIM). Treatments were formulated to maintain a forage-to-concentrate ratio of 60:40, differing only in the CS hybrids used. Two dietary treatments were assessed in a completely randomized design: total mixed ration based on conventional CS (CCS) and total mixed ration based on BMR silage. Through peak lactation (1-60 DIM), DM intake was not different between dietary treatments, whereas DM intake post-peak lactation (61-180 DIM) tended to increase by feeding the BMR diet compared with the CCS diet (25.8 vs. 24.7 kg/d). Cows fed the BMR diet tended to lose less body weight through peak lactation compared with those fed the CCS diet (-0.22 vs. -0.52 kg/d). Although milk yield was not different between dietary treatments through peak lactation, milk yield post-peak lactation increased by feeding the BMR diet compared with the CCS diet (41.0 vs. 38.8 kg/d). Yield of 3.5% fat-corrected milk was similar between dietary treatments throughout the experiment (41.4 kg/d, on average), but milk fat concentration decreased by feeding the BMR diet compared with the CCS diet post-peak lactation (3.47 vs. 3.80%). Overall milk protein concentration was similar between dietary treatments throughout the experiment (2.96%, on average), whereas milk protein yield tended to be higher for the BMR diet post-peak lactation com-pared with the CCS diet (1.19 vs. 1.13 kg/d). Feeding BMR silage with a high dietary concentration of alfalfa hay maintained more body weight, but did not affect milk production through peak lactation; however, cows fed the BMR diet post-peak lactation consumed more feed and maintained longer peak milk yield, leading to greater overall milk production and milk protein yield. [ABSTRACT FROM AUTHOR]

Background: Reduced intensity conditioning regimens in peripheral blood stem cell transplantation (PBSCT) result in a period of mixed chimerism. Its regular monitoring is important to the patient''s clinical assessment and measurement precision is essential to that process. ‘Stutter’ artefact peaks hinder chimerism estimation by mimicking minor proportions of DNA. We wished to assess the value of adding more loci to our current protocol and to look at the value of selecting only those markers unaffected by stutter artefact. Methods: Donor chimerism was monitored in 32 patients post PBSCT on five occasions using the Profiler Plus (Applied Biosystems) and Powerplex 16 (Promega) short tandem repeat (STR) kits. Results: Mean donor chimerism was not significantly altered by increasing the numbers of loci, but precision increased significantly (p=0.0002). Removing loci affected by stutter from the Powerplex 16-associated measure increased error significantly (p=0.0024), due to decreased sample size. Conclusions: Increasing available autosomal loci from 9 to 15 has increased precision of chimerism measurement and the time-consuming selection of loci compromised by stutter position alleles has proved unnecessary. [Copyright &y& Elsevier]

A seemingly routine paternity case which involved the testing of a mother, child and man led to inconclusive results as an exclusion involving only a single repeat was found at one of the 14 loci tested. This led to the testing of further loci. Only the single exclusion was found after profiling a total of 21 loci, with the addition of a further single locus providing a second exclusion. Even with both mutation events incorporated into the calculation a paternity index (PI) of 4957 was calculated, still a significant figure. However, when a second likelihood ratio was calculated assessing the likelihood of the results if the biological father of the child was the tested man or the tested man''s brother, then the results were not significant, only 0.15. This analysis led to the profiling of the tested man''s brother who matched at all 19 loci that were profiled and was concluded to be the biological father. [Copyright &y& Elsevier]

Mitochondrial DNA (mtDNA) analysis has been used both to identify individuals and to infer patterns of human evolution. We have analysed a representative population of Afro-Caribbean individuals who are residents within the UK. Sequencing has been carried out on both the hypervariable regions I (HVI) and II (HVII). In addition, a set of informative mitochondrial single nucleotide polymorphisms (SNPs) have been investigated. Comparison of these results with published data for different African populations has enabled the samples to be classified into haplogroups. Analysis of the haplogroup distribution has suggested an ancestral geographical origin for these British Afro-Caribbean samples mainly from Western Africa with some influence from Southeast Africa. [Copyright &y& Elsevier]