Ovulation rate and litter size are important reproduction traits in sheep and are of high economic value. Reproduction traits typically have low to medium heritabilities and do not exhibit a noticeable response to phenotypic selection. Therefore, inclusion of genetic information of the genes associated with reproductive ability could efficiently enhance the selection response. The most important major genes affecting prolificacy and their genetic diversities in different sheep breeds were reviewed. Different causative mutations with major effects on reproductive traits including ovulation rate and litter size have been found in various sheep breeds around the world. A general overview of the studies on main prolificacy genes showed that some alleles may express different phenotypic effects in different breeds, and thus, further studies on epistatic effects are necessary for more understanding of genetic control of reproductivity in sheep. Regarding the polygenic control of fertility traits, application of new high-throughput technologies to find new variants is essential for future studies. Moreover, genomewide association studies and genomic best linear unbiased predictions of breeding values are likely to be effective tools for genetic improvement of sheep reproductive performance traits.

No abstract

Cotton aphids, Aphis gossypii Glover (Homoptera: Aphididae), obtained from cotton, Gossypium hirsutum L., fields in the Gorgan region of northern Iran, were colonized on 'Varamin' cotton plants in a growth chamber. The development, survivorship, and life table parameters of the cotton aphid were evaluated at 27.5 +/- 1 degrees C, 65 +/- 10% RH, and aphotoperiod of 14:10 (L:D) h of artificial light on five commonly growing cotton cultivars: Varamin, 'Sealand' (relatively resistant cultivar), 'Bakhtegan', 'Sahel' (both relatively susceptible cultivars), and 'Siokra' [resistant to Bemisia tabaci (Gennadius)]. The developmental times of immature stages ranged from 4.6 d on Bakhtegan and Varamin to 6.3 d on Sealand, whereas the immature survival was 97.5 to 65% on Sahel and Siokra, respectively. On average, there were 28.7, 28.3, 23.5, 20.1, and 16.8 nymphs produced per female on Sahel, Bakhtegan, Varamin, Sealand, and Siokra, respectively. The intrinsic rate of natural increase (r(m)) for cotton aphids on Sahel was the highest, whereas the values for r(m) varied from 0.284 (nymphs per female per d) on Siokra to 0.368 on Sahel. Jackknife estimates of generation times (T), net reproductive rate (R(0)), doubling time (DT), and finite rate of increase (lambda) on these cultivars were as follows: 9.79-10.84 d for T, 9.23-23.81 nymphs per female for R(0), 2.17-3.19 d for DT, and 1.28-1.38 nymphs per female per d for lambda. Cotton aphid performance was at its highest on Sahel and lowest on Siokra.

The recognition of biodiversity in different races and lines of silkworm (Bombyx mori) is very useful for breeding programs and production of high efficiency hybrids. In this study eight groups of silkworm were selected including 103, 107, Xihang 1 and 2 of Japanese origin and 104, 110, Koming 1 and 2 of Chinese origin. The activity levels of three enzymes including alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase in haemolymph of fifth instar larva were measured. Moreover, the quantitative amount of total protein, cholesterol and glucose of haemolymph was evaluated. The data reveal that the activity level of measured macromolecules except for alkaline phosphatase were significantly different in all the groups. Hierarchical agglomerative clustering under UPGMA model separated line 104 from other groups. Two groups of Koming 1 and Xihang 1 had the most intergroup similarities.

Establishing accurate genetic similarity and dissimilarity between individuals is an essential and decisive point for clustering and analyzing inter and intra population diversity because different similarity and dissimilarity indices may yield contradictory outcomes. We assessed the variations caused by three commonly used similarity coefficients including Jaccard, Sorensen-Dice and Simple matching in the clustering and ordination of seven Iranian native silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), strains analyzed by amplified fragment length polymorphism markers. Comparisons among the similarity coefficients were made using the Spearman correlation analysis, dendrogram evaluation (visual inspection and consensus fork index - CIC), projection efficiency in a two-dimensional space, and groups formed by the Tocher optimization procedure. The results demonstrated that for almost all methodologies, the Jaccard and Sorensen-Dice coefficients revealed extremely close results, because both of them exclude negative co-occurrences. Due to the fact that there is no guarantee that the DNA regions with negative cooccurrences between two strains are indeed identical, the use of coefficients such as Jaccard and Sorensen-Dice that do not include negative co-occurrences was imperative for closely related organisms.

Composite reproductive traits are a combination of growth and reproductive traits. They have the advantage of being better attuned to the market drivers since producers are paid on a per kilogram basis and not on a per head basis. In this study, 124 Lori­­–Bakhtiari ewes were genotyped using the medium-density Illumina Ovine SNP50 array. A genome-wide association study was performed on estimated breeding values of four composite reproductive traits and genetic parameters were also estimated. The traits were litter mean weight at birth, litter mean weight at weaning, total litter weight at birth and total litter weight at weaning. Several suggestive and associated single nucleotide polymorphisms (SNPs) were identified. Neighbouring the top SNPs there were five genes, inhibin β E subunit (INHBE), inhibin β C subunit (INHBC), testis expressed 12 (TEX12), β-carotene oxygenase 2 (BCO2) and WD Repeat Domain 70 (WDR70) identified as possible candidate genes for composite reproductive traits of the Lori–Bakhtiari sheep. These genes are in pathways known to be relevant to fertility and growth characteristics. The results provide new information for the functional annotation of genes associated with fertility traits and add new evidence towards a consensus of quantitative trait loci associated with reproductive traits in sheep.

Phytophagous insects with wide host ranges often exhibit host-associated genetic structure. We used microsatellite analysis to assess the population structure of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), a serious pest on many economically important crops worldwide. We sampled aphids from five host plant species in Iran and detected strong population subdivision, with an overall multilocus FST of 0.191. The matrix of pairwise FST values indicated that differentiation between populations collected from different hosts was significantly stronger than between populations from the same hosts. Host-associated differentiation was further supported by Bayesian clustering analyses, which grouped all samples from cotton together with aubergine, and all samples from cucumber together with pumpkin and hibiscus. This adds to the growing body of evidence that many seemingly generalist aphids are in fact an assemblage of host-specialized lineages. Although we detected a clear genetic signature of clonal reproduction, the genotypic diversity of A. gossypii in Iran is much higher than in other parts of the world. Particularly samples from cotton exhibited a surprisingly high genotypic diversity, suggesting that many lineages on this host are cyclical parthenogens that engage in regular bouts of sexual reproduction. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Note: This is the accepted manuscript of the article. The definitive verion is available at www.blackwell-synergy.com Phytophagous insects with wide host ranges often exhibit host-associated genetic structure. 2The cotton aphid (Aphis gossypii) -a serious pest on many economically important crops 3 worldwide -was proposed to be such a case. We used microsatellite analysis to assess the 4 population structure of A. gossypii in Iran, including samples from five different host plants. We 5 detected strong population subdivision with an overall multilocus F ST of 0.191. The matrix of 6 pairwise F ST values indicated that differentiation between populations collected from different 7 hosts was significantly stronger than between populations from the same hosts. Host-associated 8 differentiation was further supported by Bayesian clustering analyses, which grouped all samples 9 from cotton together with aubergine, and all samples from cucumber together with pumpkin and 10 hibiscus. This adds to the growing body of evidence that many seemingly generalist aphids are in 11 fact an assemblage of host-specialized lineages. Although we detected a clear genetic signature 12 of clonal reproduction, the genotypic diversity of A. gossypii in Iran is much higher than in other 13 parts of the world. Particularly samples from cotton exhibited a surprisingly high genotypic 14 diversity, suggesting that many lineages on this host are cyclical parthenogens that engage in 15 regula...

Abstract. The use of molecular markers can support the management of endangered populations and should be combined with appropriate breeding strategies to improve productive traits avoiding the decline of the breed. The genetic variability at 10 microsatellite loci were investigated in a sample of 100 unrelated Markhoz goats (77 females and 23 males). The investigated population was reared at the Sanandaj Markhoz goat Performance Testing Station in Kurdistan, Iran. Markhoz goat, a multipurpose breed, is one of the most valuable genetic resources in Iran. All the studied loci were found to be polymorphic and a total number of 52 alleles were identified with an average number of alleles of 5.2. Moreover, some population genetic indices, such as observed and expected heterozygosity, observed and expected number of alleles, Shannon's index, Nei's expected heterozygosity, and polymorphism information content were also calculated. Despite the decreasing population size, Markhoz goat genetic diversity is still conserved. The breed seems to have a good level of genetic variability and, as a consequence, a potential margin of adaptability to environment and for future genetic improvement.