Inferring the population structure of the Maghreb sheep breeds using a medium-density SNP chip.

North Africa has a great diversity of indigenous sheep breeds whose origin is linked to its environmental characteristics and to certain historical events that took place in the region. To date, few genome-wide studies have been conducted to investigate the population structure of North African indigenous sheep. The objective of the present study was to provide a detailed assessment of the genetic structure and admixture patterns of six Maghreb sheep populations using the Illumina 50K Ovine BeadChip and comparisons with 22 global populations of sheep and mouflon. Regardless of the method of analysis used, patterns of multiple hybridization events were observed within all North African populations, leading to a heterogeneous genetic architecture that varies according to the breed. The Barbarine population showed the lowest genetic heterogeneity and major southwest Asian ancestry, providing additional support to the Asian origin of the North African fat-tailed sheep. All other breeds presented substantial Merino introgression ranging from 15% for D'man to 31% for Black Thibar. We highlighted several signals of ancestral introgression between North African and southern European sheep. In addition, we identified two opposite gradients of ancestry, southwest Asian and central European, occurring between North Africa and central Europe. Our results provide further evidence of the weak global population structure of sheep resulting from high levels of gene flow among breeds occurring worldwide. At the regional level, signs of recent admixture among North African populations, resulting in a change of the original genomic architecture of minority breeds, were also detected.

Detection of quantitative trait loci affecting non-return rate in French dairy cattle.

The purpose of this study was to map quantitative trait loci (QTL) influencing female fertility estimated by non-return rate (NRR) in the French dairy cattle breeds Prim'Holstein, Normande and Montbeliarde. The first step was a QTL detection study on NRR at 281 days after artificial insemination on 78 half-sib families including 4993 progeny tested bulls. In Prim'Holstein, three QTL were identified on Bos taurus chromosomes BTA01, BTA02 and BTA03 (p < 0.01), whereas one QTL was identified in Normande on BTA01 (p < 0.05). The second step aimed at confirming these three QTL and refining their location by selecting and genotyping additional microsatellite markers on a sub-sample of 41 families from the three breeds using NRR within 56, 90 and 281 days after AI. Only the three QTL initially detected in Prim'Holstein were confirmed. Moreover, the analysis of NRR within 56, 90 and 281 days after AI allowed us to distinguish two FF QTL on BTA02 in Prim'Holstein, one for NRR56 and one for NRR90. Estimated QTL variance was 18%, 14%, 11.5% and 14% of the total genetic variance, respectively, for QTL mapping to BTA01, BTA02 (NRR90 and NRR56) and BTA03.

Refinement of two female fertility QTL using alternative phenotypes in French Holstein dairy cattle.

Two quantitative trait loci (QTL) affecting female fertility were mapped in French dairy cattle. Phenotypes were non-return rates at 28, 56, 90 and 282 days after insemination. On chromosome 3, a QTL was significant at 1% for non-return rate at 90 days, suggesting that it affects early fertility events. An analysis of SLC35A3, which causes complex vertebral malformation, excluded this gene from the QTL interval. On chromosome 7, a QTL was almost significant (P = 0.05) for non-return rate at 282 days. This QTL was associated with abortion and stillbirth problems. Use of appropriate phenotypes appeared important for fine-mapping QTL associated with fertility.

[Cerebral venous thrombosis during pregnancy: about 7 cases]. / Thrombophlebite cerebrale survenant lors de la grossesse: a propos de 7 cas.

BACKGROUND: cerebral venous thrombophlebitis (CVT) is a rare but serious pathology. The pregnancy and especially the postpartum constitute supporting circumstances occured of the CVT. AIM: the aim of our study is to remember the symptomatology of CVT, the importance of the IRM and the angio IRM in the diagnosis of CVT, and its treatment. OBSERVATIONS: We present a retrospective study relating to 7 cases of CVT during gravidopuerperality over 7 years (1996 to 2002). The average age of our patients is 32.1 years. The CVT occured during the first trimester of the pregnancy in one case and in the postpartum in 6 cases. The symptomatology was dominated by cephalgia and the signs of intracranian hypertension. Convulsions occured in 3 cases. The diagnosis of CVT was confirmed by IRM coupled with the Angio-IRM in all cases. The treatment by heparinotherapy was instaured immediately and relayed by the Anti-Vit K as the evolution was favorable in all cases. CONCLUSION: cerebral venous thrombophebitis (CVT) is a serious pathology (especially in pregnancy and post partum). The diagnosis is performed by the magnetic resonance imaging (IRM) and the early introduction of the heparinotherapy.