Preliminary Identification of Key Genes Controlling Peach Pollen Fertility Using Genome-Wide Association Study

Previous genetic mapping helped detect a ~7.52 Mb putative genomic region for the pollen fertility trait on peach Chromosome 06 (Chr.06), which was too long for candidate gene characterization. In this study, using the whole-genome re-sequencing data of 201 peach accessions, we performed a genome-wide association study to identify key genes related to peach pollen fertility trait. The significant association peak was detected at Chr.06: 2,116,368 bp, which was in accordance with the previous genetic mapping results, but displayed largely improved precision, allowing for the identification of nine candidate genes. Among these candidates, gene PpABCG26, encoding an ATP-binding cassette G (ABCG) transporter and harboring the most significantly associated SNP (Single Nucleotide Polymorphism) marker in its coding region, was hypothesized to control peach pollen fertility/sterility based on the results of gene function comparison, gene relative expression, and nucleotide sequence analysis. The obtained results will help us to understand the genetic basis of peach pollen fertility trait, and to discover applicable markers for pre-selection in peach.

Gene co-expression network analysis reveals key potential gene modules in utero-vaginal junction associated with duration of fertility trait of breeder hens

The number of days (DN) when hens lay fertile eggs as well as the number of fertile eggs (FN) were produced after a single artificial insemination (AI), including the two duration of fertility (DF) traits. Indeed, they are the key production performance that associates with the production cost of hatching egg when its determination the interval between successive artificial inseminations. However, the relevant genes response for regulating the DF has not been uncovered yet. Therefore, we performed a weighted gene co-expression network analysis (WGCNA) to investigate the insight into co-expression gene modules on DF process in hens. The total mRNA was extracted from the utero-vaginal junction (UVJ, with the sperm storage function in hen’s oviduct which is the biological basis for DF) of 20 hens with several levels of DF traits, and performed transcriptome sequences of mRNA. As a result, three co-expression gene modules were identified to be highly correlated with DF traits. Moreover, the expression changes of top 5 hub genes in each module with DF traits were further confirmed in other 20 hens by RT-PCR. These findings highlighted the co-expression modules and their affiliated genes as playing important roles in the regulation of DF traits.

FSHR (exon 10) gene polymorphisms and its association with fertility trait in Egyptian Ossimi sheep

For the association between of Follicle stimulating hormone receptor (FSHR) gene (partial part of exon 10) polymorphisms and litter size trait in Egyptian Ossimi sheep, polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) and DNA sequencing techniques were developed. Fifty female Ossimi sheep reared under Egyptian conditions were selected according to their litter size. DNA from blood samples of these animals was isolated to amplify 250-bp of the FSHR gene influencing litter size production trait in sheep. Based on litter size, 50 animals were selected from the highest to the lowest litter size productivity during three seasons. PCR-SSCP analysis of the FSHR gene (250-bp) showed two various genotypes AA and with frequencies 0.64 and 0.36, respectively. The frequencies of the A and B alleles were 0.82 and 0.18, respectively. PCR fragment of FSHR gene (191-bp) was sequenced only in the high and low litter size productivity animals (GenBank accession numbers from MG973191 to MG973207, sequentially). The result indicated that 6SNPs (G/71, G/72, G/77, A/110, A/111, A/191) in high fertile animals, while, 10 SNPs (T/1, C/2, T/14, A/69, A/70, A/71, A/74, G/74, A/75, A/136) have found in low fertile animals. Statistically, AA and genotypes have no significant differences (p> 0.05) on litter size trait in Ossimi sheep. FSHR (exon 10) locus was moderate polymorphic (PIC= 0.25) and it can be used for high litter size productivity in Ossimi sheep as a marker-assisted selection (MAS).

Do mats matter? – Comparison of fertility traits and milk yield in dairy cows on rubber or concrete flooring

Rubber flooring in dairy cows has been discussed controversially, because different studies found as well advantages as disadvantages regarding claw health. Until today little is known regarding the effect of rubber flooring on the reproductive performance of dairy cows. Therefore, the study aimed at comparing fertility and the milk yield of dairy cows on concrete or rubber flooring. Days to first breeding (DFB), days open (DO), services per conception (SC), heat detection rate (HDR), conception rate (first service; CR1st service) and the corresponding 100 days in milk (DIM) milk yield were evaluated for 139 lactation periods of 91 cows of the University Munich Livestock Center dairy herd. The cows entered the study as heifers and were housed on the same flooring system during their whole productive life. All cows underwent the same management, feeding, and climatic conditions. A mixed model procedure was used to analyse data. Cows on rubber (RSF) compared with cows on concrete flooring (CSF) showed less DFB (76.8/94.6; P<0.01), less DO (98.8/138.4; P<0.01), and no difference regarding SC (1.5/1.7; P=0.267). Furthermore, no differences regarding the 100 DIM milk yield could be established. The calculation of HDR (54.9%/27.9%) and CR1st service (39.4/29.4) showed also high advantages for the rubber flooring. It was concluded that rubber flooring affects an earlier onset of regular oestrus behaviour and improves the economically sensible fertility trait of calving interval by earlier pregnancy and less days open but does not cause higher milk yield.