Assessment of cattle genetic introgression into domestic yak populations using mitochondrial and microsatellite DNA markers

Hybridization between yak Poephagus grunniens and taurine Bos taurus or indicine B. indicus cattle has been widely practiced throughout the yak geographical range, and gene flow is expected to have occurred between these species. To assess the impact of cattle admixture on domestic yak, we examined 1076 domestic yak from 29 populations collected in China, Bhutan, Nepal, India, Pakistan, Kyrgyzstan, Mongolia and Russia using mitochondrial DNA and 17 autosomal microsatellite loci. A cattle diagnostic marker-based analysis reveals cattle-specific mtDNA and/or autosomal microsatellite allele introgression in 127 yak individuals from 22 populations. The mean level of cattle admixture across the populations, calculated using allelic information at 17 autosomal microsatellite loci, remains relatively low (mY(cattle) = 2.66 +/- 0.53% and Q(cattle) = 0.69 +/- 2.58%), although it varies a lot across populations as well as among individuals within population. Although the level of cattle admixture shows a clear geographical structure, with higher levels of admixture in the Qinghai-Tibetan Plateau and Mongolian and Russian regions, and lower levels in the Himalayan and Pamir Plateau region, our results indicate that the level of cattle admixture is not significantly correlated with the altitude across geographical regions as well as within geographical region. Although yak-cattle hybridization is primarily driven to produce F-1 hybrids, our results show that the subsequent gene flow between yak and cattle took place and has affected contemporary genetic make-up of domestic yak. To protect yak genetic integrity, hybridization between yak and cattle should be tightly controlled.

Use of allozyme markers to determine the genetic structure of hatchery population of Thai pangas, Pangasius hypophthalmus of Jessore, Bangladesh

Genetic structure of hatchery population of Thai pangas (Pangasius hypophthalmus) of Jessore region, Bangladesh has been investigated from 1 January 2004 to 31 December 2004. Samples for this study were collected from five fish hatcheries viz. Asrom, Banchte Shekha, Chowdhury, Maola and Rezaul Haque. The enzymes were encoded by 15 gene loci: Adh-1*, Est-1*, G3pdh-2*, Gpi-1*, Gpi-2*, Idhp-1*, Idhp-2*, Ldh-1*, Ldh-2*, Mdh-1*, Mdh-2*, Pgm*, Sdh-1*, Sdh-2* and Sod*. Among them four (Est-1*, G3pdh-2*, Gpi-2*and Pgm*) were found to be polymorphic in different populations but only Gpi-2* was polymorphic in all the sampled populations. The mean proportion of polymorphic loci per population was the highest (26.7%) in Banchte Shekha hatchery while the mean proportion of heterozygous loci was 13.33% per individual in Banchte Shekha and Maola hatcheries. The UPGMA dendrogram of Nei's (1972) genetic distances indicated a relationship between the genetic distance and geographical difference. High genetic variability in stocks of Thai pangas was observed in the Banchte Shekha and Maola hatcheries and less variability was found in the other three hatcheries.

A markov chain Monte Carlo method for estimating population mixing using Y-chromosome markers: Mixing of the Han people in China

We present a new approach for estimating mixing between populations based on non-recombining markers, specifically Y-chromosome microsatellites. A Markov chain Monte Carlo (MCMC) Bayesian statistical approach is used to calculate the posterior probability

Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism

Fig trees are pollinated by fig wasps, which also oviposit in female flowers. The wasp larvae gall and eat developing seeds. Although fig trees benefit from allowing wasps to oviposit, because the wasp offspring disperse pollen, figs must prevent wasps fr

The evolution of intermediate castration virulence and ant coexistence in a spatially structured environment

Theory suggests that spatial structuring should select for intermediate levels of virulence in parasites, but empirical tests are rare and have never been conducted with castration (sterilizing) parasites. To test this theory in a natural landscape, we co

Co-expression of CD173 (H2) and CD174 (Lewis Y) with CD44 suggests that fucosylated histo-blood group antigens are markers of breast cancer-initiating cells

Histo-blood group antigens CD173 (H2) and CD174 (Lewis Y) are known to be developmentally regulated carbohydrate antigens which are expressed to a varying degree on many human carcinomas. We hypothesized that they might represent markers of cancer-initiating cells (or cancer stem cells, CSC). In order to test this hypothesis, we examined the co-expression of CD173 and CD174 with stem cell markers CD44 and CD133 by flow cytometry analysis, immunocytochemistry, and immunohistochemistry on cell lines and tissue sections from breast cancer. In three breast cancer cell lines, the percentage of CD173(+)/CD44(+) cells ranged from 17% to > 60% and of CD174(+)/CD44(+) from 21% to 57%. In breast cancer tissue sections from 15 patients, up to 50% of tumor cells simultaneously expressed CD173, CD174, and CD44 antigens. Co-expression of CD173 and CD174 with CD133 was also observed, but to a lesser percentage. Co-immunoprecipitation and sandwich ELISA experiments on breast cancer cell lines suggested that CD173 and CD174 are carried on the CD44 molecule. The results show that in these tissues CD173 (H2) and CD174 (LeY) are associated with CD44 expression, suggesting that these carbohydrate antigens are markers of cancer-initiating cells or of early progenitors of breast carcinomas.

Genetic diversity and taxonomic implication of Cordyceps sinensis as revealed by RAPD markers

Random amplified polymorphic DNA (RAPD) markers are used to investigate genetic variation and evolutionary relationships of 29 samples of Cordyceps sinensis from different geographical populations on the Qinghai-Tibet plateau. Out of 137 RAPD bands scored, 100 are polymorphic. A correlation is revealed between geographical distance and genetic distance. The molecular phylogenetic tree suggests that the 29 samples are divided into three notable clusters, corresponding to the geographical populations, i.e., the north population (NP), middle population (MP), and south population (SP). The NP consists of 7 northern samples from Menyuan, Maqu, and Luqu, the MP consists of 8 samples from Yushu and Chengduo, and the SP consists of 14 samples from Byma Snow Mountain, Renzhi Snow Moutain, Chongcaoxiwa, and Dacaodi. It is demonstrated that extensive genetic diversity is found among different geographical populations of C. sinensis. The genetic diversity pattern of C. sinensis may be caused by the founder effects. The taxonomic status of NP, MP, and SP populations should be that they are different subspecies rather than different species.

Isolation and characterization of microsatellite markers for the endangered Taxus yunnanensis

Eleven polymorphic microsatellite loci were characterized for the endangered conifer Taxus yunnanensis. Eight loci were isolated through SSR-anchored PCR, one locus was developed by cross-species amplification tests, while the last two loci were obtained

Phylogenetic incongruence between nuclear and mitochondrial markers in the Asian colobines and the evolution of the langurs and leaf monkeys

Evidence of incongruence between mitochondrial and nuclear gene trees is now becoming documented with increasing frequency. Among the Old World monkeys, this discordance has been well demonstrated in the Cercopithecinae, but has not yet been investigated

Genetic diversity of Bartail flathead (Platycephalus indicus (Linnaeus,1758)) using AFLP markers in Persian Gulf

Platycephalus indicus is a large benthic fish that inhabits temperate and tropical coastal waters of the Indo-West Pacific and found on sand or mud bottom in vary shallow area of estuary and near shore to depth of 25m. This species is dominant species of platycephalidae family, in Khuzestan, Bushehr and Hormozgan provinces and mainly is captured by bottom trawl, gillnet and moshta in Hormozgan. This study was designed to evaluate population variation and differentiation of bartail flathead (Platycephalus indicus (Linnaeus, 1785))in the Iranian waters of Persian Gulf using the morphometric and meristic characters and by AFLP marker. . A total 180 fish specimens were collected by gill net from six station(khor mosa, bahrekan, shif, motaf, charak and bandar abbas) that was 30 individual related to every station in Iranian shores of Persian Gulf . 28 morphometric factors and 11meristic specialties were measured and morphometric factors was standardized with Beacham formula. Univariate analysis of variance (One-way ANOVA) revealed significant differences with varying degrees between the means for 21 standardized morphometric measurements and 6 meristic counts that showed high significant differences between the six stations sampling. Discriminate function analysis (DFA) or the overall random assignment of individuals into their original groups was for morphometric and meristic characters was 47.9% and 53.9% respectively. The data were subjected to a principle component analysis (PCA) which grouped in eight and four factors for morphometric and meristic charactersrespectively.. Genetic diversity of six populations of bartail flathead (Platycephalus indicus) was investigated using amplified fragment length polymorphism (AFLP). A total of 118 reproducible bands amplified with ten AFLP primer combinations were obtained from 42 fishes that were collected from six different locations in the northern of Persian Gulf. The percentage of polymorphic bands was 57.06%. Average of Nei’s genetic diversity was 0.200±0.008, and Average of Shannon’s index was 0.300±0.011. The results of AMOVA analysis indicated that 66% of the genetic variation contained within populations and 34% occurred among populations and gene flow was 0.6454.The estimated level of population differentiation asmeasured by average Fst value across all loci was 0.327. Plotting discriminant functions 1 and 2 and UPGMA dendrograms based on Euclidian distance and genetic distance also showed at least five separate populations of bartail flathead in the northern Persian Gulf.

Physiological and biochemical study of over-ripened oocyte in the cultivated Caspian brown trout (Salmo trutta caspius) and determination of egg quality markers

To determine the best time for egg stripping after ovulation and over-ripened oocyte in the Caspian brown trout (Salmo trutta caspius), the eggs were retained in the parental abdominal cavity for 40 days post-ovulation (DPO) at 7±0.6°C. Eggs were stripped every 10-day interval in 4 treatment and were fertilized with a pool of semen obtained from 8 males. Also, the physiology and biochemistry of the eggs and ovarian fluids were studied. Results showed that the level of eyed eggs and hatched alevins declined with over-ripening time: that is, the expected amounts (90.65 ± 6.28% for eyeing and 86.33 ± 6.82% for hatching) in newly ovulated eggs (0–10 DPO) decreased to 0.67 ± 1.34% and 0.49 ± 0.98%, respectively, in over-ripened eggs (30–40 DPO). However, larval abnormalities remained constant for 30-days after ovulation. During the course of oocyte over-ripening, the pH of the ovarian fluid significantly decreased and the concentration of glucose, protein, calcium, iron, and aspartate aminotransferase activity significantly increased. Moreover, the concentration of protein, triglycerides, and aspartate aminotransferase activity in the eggs also changed. In the newly ovulated egg, the yolk consisted of homogenous tissue and its perivitelline space diameter had no considerable differences. With over-ripening, the yolk became heterogeneous, while chorion diameter and micropyle did not change. The perivitelline space diameter varied among different areas. The present study demonstrated that the best time to take Caspian brown trout eggs after ovulation at 7± 0.6°C was up to 10 DPO. Among the studied parameters of the egg and ovarian fluid, egg quality was related to both ovarian fluid parameters (e.g., pH, protein, aspartate aminotransferase, glucose, cholesterol, triglycerides, calcium, iron) and egg parameters (e.g., cholesterol, triglycerides, iron, aspartate aminotransferase). Thus, these parameters can be used as a egg quality markers in this species.