Mode Of Reproduction Research Articles

Phylogenetic analysis of viviparity, matrotrophy, and other reproductive patterns in chondrichthyan fishes.

The reproductive diversity of extant cartilaginous fishes (class Chondrichthyes) is extraordinarily broad, reflecting more than 400 million years of evolutionary history. Among their many notable reproductive specialisations are viviparity (live-bearing reproduction) and matrotrophy (maternal provision of nutrients during gestation). However, attempts to understand the evolution of these traits have yielded highly discrepant conclusions. Here, we compile and analyse the current knowledge on the evolution of reproductive diversity in Chondrichthyes with particular foci on the frequency, phylogenetic distribution, and directionality of evolutionary changes in their modes of reproduction. To characterise the evolutionary transformations, we amassed the largest empirical data set of reproductive parameters to date covering nearly 800 extant species and analysed it via a comprehensive molecular-based phylogeny. Our phylogenetic reconstructions indicated that the ancestral pattern for Chondrichthyes is 'short single oviparity' (as found in extant holocephalans) in which females lay successive clutches (broods) of one or two eggs. Viviparity has originated at least 12 times, with 10 origins among sharks, one in batoids, and (based on published evidence) another potential origin in a fossil holocephalan. Substantial matrotrophy has evolved at least six times, including one origin of placentotrophy, three separate origins of oophagy (egg ingestion), and two origins of histotrophy (uptake of uterine secretions). In two clades, placentation was replaced by histotrophy. Unlike past reconstructions, our analysis reveals no evidence that viviparity has ever reverted to oviparity in this group. Both viviparity and matrotrophy have arisen by a variety of evolutionary sequences. In addition, the ancestral pattern of oviparity has given rise to three distinct egg-laying patterns that increased clutch (brood) size and/or involved deposition of eggs at advanced stages of development. Geologically, the ancestral oviparous pattern arose in the Paleozoic. Most origins of viviparity and matrotrophy date to the Mesozoic, while a few that are represented at low taxonomic levels are of Cenozoic origin. Coupled with other recent work, this review points the way towards an emerging consensus on reproductive evolution in chondrichthyans while offering a basis for future functional and evolutionary analyses. This review also contributes to conservation efforts by highlighting taxa whose reproductive specialisations reflect distinctive evolutionary trajectories and that deserve special protection and further investigation.

Clonal genomic population structure of Beauveria brongniartii and Beauveria pseudobassiana: Pathogens of the common European cockchafer (Melolontha melolontha L.).

Beauveria brongniartii is a fungal pathogen that infects the beetle Melolontha melolontha, a significant agricultural pest in Europe. While research has primarily focused on the use of B. brongniartii for controlling M. melolontha, the genomic structure of the B. brongniartii population remains unknown. This includes whether its structure is influenced by its interaction with M. melolontha, the timing of beetle-swarming flights, geographical factors, or reproductive mode. To address this, we analysed genome-wide SNPs to infer the population genomics of Beauveria spp., which were isolated from infected M. melolontha adults in an Alpine region. Surprisingly, only one-third of the isolates were identified as B. brongniartii, while two-thirds were distributed among cryptic taxa within B. pseudobassiana, a fungal species not previously recognized as a pathogen of M. melolontha. Given the prevalence of B. pseudobassiana, we conducted analyses on both species. We found no spatial or temporal genomic patterns within either species and no correlation with the population structure of M. melolontha, suggesting that the dispersal of the fungi is independent of the beetle. Both species exhibited clonal population structures, with B. brongniartii fixed for one mating type and B. pseudobassiana displaying both mating types. This implies that factors other than mating compatibility limit sexual reproduction. We conclude that the population genomic structure of Beauveria spp. is primarily influenced by predominant asexual reproduction and dispersal.

MIKE: an ultrafast, assembly-, and alignment-free approach for phylogenetic tree construction.

Constructing a phylogenetic tree requires calculating the evolutionary distance between samples or species via large-scale resequencing data, a process that is both time-consuming and computationally demanding. Striking the right balance between accuracy and efficiency is a significant challenge. To address this, we introduce a new algorithm, MIKE (MinHash-based k-mer algorithm). This algorithm is designed for the swift calculation of the Jaccard coefficient directly from raw sequencing reads and enables the construction of phylogenetic trees based on the resultant Jaccard coefficient. Simulation results highlight the superior speed of MIKE compared to existing state-of-the-art methods. We used MIKE to reconstruct a phylogenetic tree, incorporating 238 yeast, 303 Zea, 141 Ficus, 67 Oryza, and 43 Saccharum spontaneum samples. MIKE demonstrated accurate performance across varying evolutionary scales, reproductive modes, and ploidy levels, proving itself as a powerful tool for phylogenetic tree construction. MIKE is publicly available on Github at https://github.com/Argonum-Clever2/mike.git.

Influence of ovarian torsion on reproductive outcomes and mode of delivery.

To investigate differences in reproductive outcomes among patients before and following ovarian torsion. In this retrospective cohort study, we investigated the reproductive outcomes of patients who underwent surgery for ovarian torsion between 1988 and 2015 in a tertiary medical center. Data on deliveries before and after ovarian torsion were compared. During the study period, 199 women underwent surgery due to ovarian torsion. The majority (91.4%; n = 182) underwent detorsion, and 8.6% (n = 17) underwent unilateral adnexectomy. At the time of the torsion, 27.6% (n = 55) of patients were pregnant. Among women who suffered from ovarian torsion, about half (52%) of the deliveries occurred before the torsion and 48% following the torsion. No significant difference in the live birth rate was noted (p = 0.19). The fertility treatment rate in our cohort was 7.5% before and 5% after the torsion (p = 0.01). In addition, live birth, cesarean delivery, and fertility treatment rates were similar in women who underwent detorsion vs. those who had adnexectomy. Surgically treated ovarian torsion does not appear to negatively influence fertility and live birth potential.

Plant regeneration capacity in seeds of three species of Miconia (Melastomataceae) may be related to endogenous polyamine profiles.

In plant tissue culture, differences in endogenous levels of species-specific plant growth regulators (PGRs) may explain differences in regenerative capacity. In the case of polyamines (PAs), their dynamics and distribution may vary between species, genotypes, tissues, and developmental pathways, such as sexual reproduction and apomixis. In this study, for the first time, we aimed to assess the impact of varying endogenous PAs levels in seeds from distinct reproductive modes in Miconia spp. (Melastomataceae), on their in vitro regenerative capacity. We quantified the free PAs endogenous content in seeds of Miconia australis (obligate apomictic), Miconia hyemalis (facultative apomictic), and Miconia sellowiana (sexual) and evaluated their in vitro regenerative potential in WPM culture medium supplemented with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The morphogenic responses were characterized by light microscopy and scanning electron microscopy and discussed regarding the endogenous PAs profiles found. Seeds of M. sellowiana presented approximately eight times more putrescine than M. australis, which was associated with a higher percentage of regenerated calluses (76.67%) than M. australis (5.56%). On the other hand, spermine levels were significantly higher in M. australis. Spermine is indicated as an inhibitor of auxin-carrying gene expression, which may have contributed to its lower regenerative capacity under the tested conditions. These findings provide important insights into in vitro morphogenesis mechanisms in Miconia and highlight the significance of endogenous PA levels in plant regeneration. These discoveries can potentially optimize future regeneration protocols in Miconia, a plant group still underexplored in this area.

The Poultry Red Mite, Dermanyssus gallinae, travels far but not frequently, and takes up permanent residence on farms

Management of Dermanyssus gallinae, a cosmopolitan hematophagous mite responsible for damage in layer poultry farming, is hampered by a lack of knowledge of its spatio-temporal population dynamics. Previous studies have shown that the circulation of this pest between farms is of strictly anthropogenic origin, that a mitochondrial haplogroup has been expanding on European farms since the beginning of the 21st century and that its local population growth may be particularly rapid. To refine our understanding of how D. gallinae spreads within and among farms, we characterized the genetic structure of mite populations at different spatial scales and sought to identify the main factors interrupting gene flow between poultry houses and between mitochondrial haplogroups. To this end, we selected and validated the first set of nuclear microsatellite markers for D. gallinae and sequenced a region of the CO1-encoding mitochondrial gene in a subsample of microsatellite-genotyped mites. We also tested certain conditions required for effective contamination of a poultry house through field experimentation, and conducted a survey of practices during poultry transfers. Our results confirm the role of poultry transport in the dissemination of mite populations, but the frequency of effective contamination after the introduction of contaminated material into poultry houses seems lower than expected. The high persistence of mites on farms, even during periods when poultry houses are empty and cleaned, and the very large number of nodes in the logistic network (large number of companies supplying pullets or transporting animals) undoubtedly explain the very high prevalence on farms. Substantial genetic diversity was measured in farm populations, probably as a result of the mite's known haplodiploid mode of sexual reproduction, coupled with the dense logistic network. The possibility of the occasional occurrence of asexual reproduction in this sexually reproducing mite was also revealed in our analyses, which could explain the extreme aggressiveness of its demographic dynamics under certain conditions.

Evolution of alternative reproductive systems in Bacillus stick insects.

Reproduction is a key feature of all organisms, yet the way in which it is achieved varies greatly across the tree of life. One striking example of this variation is the stick insect genus Bacillus, in which five different reproductive modes have been described: sex, facultative and obligate parthenogenesis, and two highly unusual reproductive modes: hybridogenesis and androgenesis. Under hybridogenesis, the entire genome from the paternal species is eliminated and replaced each generation by mating with the corresponding species. Under androgenesis, an egg is fertilized, but the developing diploid offspring bear two paternal genomes and no maternal genome, as a consequence of unknown mechanisms. Here, we reevaluate the previous descriptions of Bacillus lineages and the proposed F1 hybrid ancestries of the hybridogenetic and obligately parthenogenetic lineages (based on allozymes and karyotypes) from Sicily, where all these reproductive modes are found. We generate a chromosome-level genome assembly for a facultative parthenogenetic species (B. rossius) and combine extensive field sampling with RADseq and mtDNA data. We identify and genetically corroborate all previously described species and confirm the ancestry of hybrid lineages. All hybrid lineages have fully retained their F1 hybrid constitution throughout the genome, indicating that the elimination of the paternal genome in hybridogens is always complete and that obligate parthenogenesis in Bacillus hybrid species is not associated with an erosion of heterozygosity as known in other hybrid asexuals. Our results provide a stepping stone toward understanding the transitions between reproductive modes and the proximate mechanisms of genome elimination.

Hurdles in investigating UVB damage in the putative ancient asexual Darwinula stevensoni (Ostracoda, Crustacea)

Ostracoda or mussel-shrimps are small, bivalved Crustacea. Because of their excellent fossil record and their broad variety of reproductive modes, ostracods are of great interest as a model group in ecological and evolutionary research. Here, we investigated damage and repair from one of the most important biological mutagens, namely UVB radiation, in the putative ancient asexual ostracod Darwinula stevensoni from Belgium. We applied three different methods: the Polymerase Inhibition (PI) assay, Enzyme-Linked Immuno Sorbent Assay (ELISA) and dot blot. All three techniques were unsuccessful in quantifying UVB damage in D. stevensoni. Previous experiments have revealed that the valves of D. stevensoni provide an average UVB protection of approximate 60%. Thus, UVB damage could be too little to make quantitative experiments work. Additionally, variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches to quantify damage. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated relative lethal UVB dose at 4°C was with 50 kJ/m2, significantly lower than at room temperature, with 130 kJ/m2. This could either indicate lack of adaptation to low temperatures and/or the presence of metabolic processes active at room temperature protecting against UVB damage in D. stevensoni. The latter possibility could also explain why the estimated relative lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, despite the valves of D. stevensoni providing less protection. If such metabolic processes can repair UVB damage quickly, this may provide an alternative explanation why we could not quantify UVB damage in D. stevensoni.

Casting light on the European anchovy: from biology to conservation and industry

This manuscript explores the role of European anchovies (Engraulis encrasicolus) in the central Mediterranean Region, shedding light on their ecological significance, conservation challenges, and sustainable utilization. The European anchovy is one of Europe’s most important fish resources in the Mediterranean basin, and it is considered a keystone species, playing a pivotal role in both ecological and socio-economic dimensions. However, in recent decades, European anchovy, together with Sardina pilchardus (commonly known as European sardine), has suffered a population decline for several reasons. Consequently, it is necessary to improve the management of anchovy fisheries by understanding the reproductive modes and characteristics, the influence of currents on the passive transport of eggs and larvae, the feeding habits, the environmental adaptability (e.g., salinity), and the distribution of ecotypes along the Italian coasts. Such information is fundamental for the management of fisheries, especially artisanal ones, and to control frauds, especially in protected, geographically referred, and traditional high-quality commercial products. Various aspects, ranging from their population dynamics to their industrial processing and the ecological implications of these activities were delved, highlighting the knowledge about anchovy populations and ecotypes and its importance in maintaining ecosystem balance and sustaining human communities. The ecological interaction of anchovies within the food web, as essential data in the conservation actions and management of these resources was emphasized. In addition, the metabolic and stomach contents diversity among anchovy populations and ecotypes was discussed, enhancing our understanding of their adaptability to varying environmental conditions. The manuscript then explores the traditional and industrial processing of anchovies, encompassing aspects ranging from fishing techniques (i.e., methods of capture) to their industrial significance, sustainability concerns, issues of fraud, and the establishment of geographical traceability. Finally, the opportunities for sustainable and biotechnological utilization of anchovy discards were also further explored, demonstrating the potential for waste reduction and resource optimization.

A novel strategy to study apomixis, automixis, and autogamy in plants

Key messageThe combination of a flow cytometric seed screen and genotyping of each single seed offers a cost-effective approach to detecting complex reproductive pathways in flowering plants.Reproduction may be seen as one of the driving forces of evolution. Flow cytometric seed screen and genotyping of parents and progeny are commonly employed techniques to discern various modes of reproduction in flowering plants. Nevertheless, both methods possess limitations constraining their individual capacity to investigate reproductive modes thoroughly. We implemented both methods in a novel manner to analyse reproduction pathways using a carefully selected material of parental individuals and their seed progeny. The significant advantage of this approach lies in its ability to apply both methods to a single seed. The introduced methodology provides valuable insights into discerning the levels of apomixis, sexuality, and selfing in complex Rubus taxa. The results may be explained by the occurrence of automixis in Rubus, which warrants further investigation. The approach showcased its effectiveness in a different apomictic system, specifically in Taraxacum. Our study presents a comprehensive methodological approach for determining the mode of reproduction where flow cytometry loses its potential. It provides a reliable and cost-effective method with significant potential in biosystematics, population genetics, and crop breeding.

The origins and drivers of sexual size dimorphism in sharks.

While sexual size dimorphism (SSD) is abundant in nature, there is huge variation in both the intensity and direction of SSD. SSD results from a combination of sexual selection for large male size, fecundity selection for large female size and ecological selection for either. In most vertebrates, it is variation in the intensity of male-male competition that primarily underlies variation in SSD. In this study, we test four hypotheses regarding the adaptive value of SSD in sharks-considering the potential for each of fecundity, sexual, ecological selection and reproductive mode as the primary driver of variation in SSD between species. We also estimate past macroevolutionary shifts in SSD direction/intensity through shark phylogeny. We were unable to find evidence of significant SSD in early sharks and hypothesise that SSD is a derived state in this clade, that has evolved independently of SSD observed in other vertebrates. Moreover, there is no significant relationship between SSD and fecundity, testes mass or oceanic depth in sharks. However, there is evidence to support previous speculation that reproductive mode is an important determinant of interspecific variation in SSD in sharks. This is significant as in most vertebrates sexual selection is thought to be the primary driver of SSD trends, with evidence for the role of fecundity selection in other clades being inconsistent at best. While the phylogenetic distribution of SSD among sharks is superficially similar to that observed in other vertebrate clades, the relative importance of selective pressures underlying its evolution appears to differ.

Description of two new Pristionchus species from South Korea.

Based on molecular markers, mating experiments, morphological observations and ecological data, two Pristionchus species (Nematoda: Diplogastridae) new to science are described. Both were collected from different Scarabaeoid beetles in South Korea, have a gonochoristic mode of reproduction and fall into a sub-clade of the pacificus clade. Pristionchus coreanus n. sp. does not show a eurystomatous morph under laboratory conditions and might therefore be suitable for the study of gain and loss of polymorphism. Pristionchus hangukensis n. sp. is phylogenetically close to Chinese and Japanese species and helps to separate an Asian clade from an American clade.

Population structure of three invasive congeneric teasel (Dipsacus) species

AbstractThree species of the Old World genus Dipsacus L. are considered invasive in the Americas, yet they may differ in how they spread and reproduce and in their genetic diversity. Differences in invasion method may suggest that different management techniques are needed for each species. We performed genetic analyses on 572 plants in 69 populations from the United States, Argentina, and Eurasia with the goals of analyzing taxonomy, diversity, mode of reproduction, population structure, and founder effect of each of these species’ invasions, as well as looking for evidence of recent or ongoing hybridization. We found Indian teasel [Dipsacus sativus (L.) Honck.] to be lowest in diversity and possibly reliant on self-pollination more than the other species, Fuller’s teasel (Dipsacus fullonum L.) and cutleaf teasel (Dipsacus laciniatus L.). We found no evidence of hybridization within the invasions and no support for D. sativus as a subspecies of D. fullonum. The closest genetic matches of D. fullonum from the United States to the native range were with Hungary and Spain, while the closest match for D. fullonum between Argentina and the native range was with Spain. Dipsacus laciniatus from the United States most closely matched with samples from Russia. Population structure information regarding these three weedy Dipsacus species can help us understand their invasive processes as well as give insight into their management and the development of a biological control program.

The relation between apomictic seed production and morpho-physiological characteristics in a world collection of castor bean (Ricinus communis L.)

Ricinus communis is one of the most important oilseed plants with many medicinal and industrial applications. Variation in 30 genotypes of castor bean collected from different regions of the world was evaluated for two consecutive years and the difference in seed production with two different reproductive modes (including apomixis and open-pollination) was compared based on yield components, agronomic traits, and phytochemical properties. Results of data analysis demonstrated that castor bean has the ability for a wide range of apomixis for seed production and the highest percentages of apomixis ability in the first and second years were 86.3% and 92.31%, respectively. Apomixis ability had a high positive correlation with yield components, seed oil content, and the amount of leaf rutin. Two genotypes from Brazil and Syria revealed the highest phenolic content in the first and second years, respectively. In addition, the Afghanistan genotype in two modes of apomixis and open-pollination in the first year and the Syria and Yazd genotypes in apomixis and open-pollination modes, respectively, in the second year showed the highest content of seed fatty acids. It is possible to maintain superior genotypes of castor bean in terms of phytochemical traits, yield, and oil quality through apomixis reproduction.

Exploring floral morphoanatomy and embryology in wild populations of Chrysolaena flexuosa (Vernonia, Asteraceae): a contribution to understanding its ornamental potential.

Chrysolaena flexuosa (Sims.) H. Rob. is a South American species in the tribe Vernonieae, with potential ornamental value: it has attractive inflorescences, is suitable for pot cultivation, and its cypselae are useful for dried flower arrangements. Apart from studies on the growth dynamics of this species under cultivation, chromosome number, DNA content, ploidy level, size, pollen viability, and the characterization of phenotypic and genetic variability, it is noteworthy that other aspects regarding the floral architecture, reproductive mode, and gametophyte formation of C. flexuosa have not yet been studied. For this reason, our study encompasses a floral morphoanatomical survey and a comprehensive assessment of gametophyte development in the species. As a result of this study, we report new floral morphotypes, confirming that the morphological variability of the species might be greater than speculated. The morphoanatomy of the androecium and gynoecium and the male and female gametophyte developmental characteristics are uniform in all the populations studied despite the different ploidy levels. Chrysolaena flexuosa has five tetrasporangiate stamens of the dicotyledonous type of development; all the populations studied displayed a unilocular inferior ovary with a single anatropous, unitegumented, and tenuinucellar ovule. Given that all the embryo sacs observed were of the Polygonum-type development regardless of the ploidy level, we infer that the populations analyzed are fertile and undergo sexual reproduction. Our results not only contribute further research in the field of breeding systems and propagation of this species, but also promote the successful introduction of C. flexuosa to the plant ornamental market.

A novel sexual system in male gametophytes of Laminaria pallida (Phaeophyceae)

ABSTRACT Brown algae (Phaeophyceae) exhibit a wide diversity of sexual systems, reproductive modes and life histories. The evolution of this diversity has often involved transitions between sexual systems, which may influence genetic diversity and diversification, and phenotypic evolution. This study reports a novel sexual system in kelp. We identified male gametophyte strains of Laminaria pallida that, despite presenting morphological features typical of a male, developed both antheridia and egg-like structures, which suggest an incomplete suppression of femaleness during sexual determination of gametophytes. The sperm released by these variant male gametophytes successfully fertilize eggs produced by female gametophytes, developing into sporophytes with normal morphologies. However, morphologically abnormal sporophytic offspring were formed in isolated variant male gametophytes, indicating that the egg-like structures were not successfully self-fertilized by sperm. The causes of the unsuccessful intragametophytic selfing are unknown, but absence of pheromone production by the egg-like structures is a hypothesis suggested by available evidence. Partial co-sexuality is clearly inherited, as all male gametophyte strains descended from the same sporophyte developed egg-like structures. Further investigation into the genetics and maturation of male partheno-sporophytes will help to estimate the potential effects of this mechanism on natural populations.

Phylogeny of the genus Loxospora s.l. (Sarrameanales, Lecanoromycetes, Ascomycota), with Chicitaea gen. nov. and five new combinations in Chicitaea and Loxospora.

Loxospora is a genus of crustose lichens containing 13 accepted species that can be separated into two groups, based on differences in secondary chemistry that correlate with differences in characters of the sexual reproductive structures (asci and ascospores). Molecular phylogenetic analyses recovered these groups as monophyletic and support their recognition as distinct genera that differ in phenotypic characters. Species containing 2'-O-methylperlatolic acid are transferred to the new genus, Chicitaea Guzow-Krzem., Kukwa & Lendemer and four new combinations are proposed: C.assateaguensis (Lendemer) Guzow-Krzem., Kukwa & Lendemer, C.confusa (Lendemer) Guzow-Krzem., Kukwa & Lendemer, C.cristinae (Guzow-Krzem., Łubek, Kubiak & Kukwa) Guzow-Krzem., Kukwa & Lendemer and C.lecanoriformis (Lumbsch, A.W. Archer & Elix) Guzow-Krzem., Kukwa & Lendemer. The remaining species produce thamnolic acid and represent Loxospora s.str. Haplotype analyses recovered sequences of L.elatina in two distinct groups, one corresponding to L.elatina s.str. and one to Pertusariachloropolia, the latter being resurrected from synonymy of L.elatina and, thus, requiring the combination, L.chloropolia (Erichsen) Ptach-Styn, Guzow-Krzem., Tønsberg & Kukwa. Sequences of L.ochrophaea were found to be intermixed within the otherwise monophyletic L.elatina s.str. These two taxa, which differ in contrasting reproductive mode and overall geographic distributions, are maintained as distinct, pending further studies with additional molecular loci. Lectotypes are selected for Lecanoraelatina, Pertusariachloropolia and P.chloropoliaf.cana. The latter is a synonym of Loxosporachloropolia. New primers for the amplification of mtSSU are also presented.

Reproduction mode and Strain effects on Rabbit Breeding Performances

This study was carried out to determine the impact of the mode of reproduction and the strain (male and female) of rabbits on some zootechnical and reproduction parameters. For that, monitoring was carried out in 2019 in the region of Setif (North Eastern Algeria) on a semi-intensive breeding of 25 crossbreed rabbits. The statistical analysis showed a very highly significant effect of the mode of reproduction on the number of mating per fertilizing mating (P= 0.0001) with an average of 1 ± 0 in AI (Fertility rate of 80%), while it was of 1.45 ± 0.51 in natural breeding with a fertility rate of 61%. The weight of the rabbits at weaning was higher in AI than in natural mating (587.25 ± 338.19 g vs. 575.0 ± 375.44 g, respectively). The results relating to the number of total born, born alive, weaned rabbits, the farrowing-mating interval and the farrowing-fertilizing mating interval in natural mode were respectively of (7.4 ± 3.12), (4.55 ± 3.12), (4.55 ± 3.12), (12.65 ± 2.30), (19.15 ± 3.58); and in AI: (6.90 ± 4.12), (5.75 ± 4 .12), (5.75 ± 4.12), (11.65 ± 2.05), (18.99 ± 3.2) (P>0.05). Furthermore, and regarding the strains, data revealed that the females did not have any significant effect on the variables studied. On the contrary, the male had a very highly significant effect on the number of mating per fertilizing mating (p = 0.000), while it had no impact on the other parameters (P>0.05). To conclude, the control and the management of reproduction is the key to success in rabbit breeding, thus the combination of rearing condition and genetic effects is the main tool for making rabbit farming successful.

Utjecaj sezone parenja i stanja tijela na zootehničke parametre ouled djellal ovaca u polupustinjskim područjima

In this study, a database was created by monitoring 3000 Ouled Djellal ewes, belonging to ten breeding farms and representing two modes of reproduction management. The data collected make it possible to measure the reproductive performance of females and to determine the influence of non-genetic factors on different parameters. The Body Condition Score (BCS) was calculated to compare performance in relation with breeding conditions. The results showed that fertility and prolificacy accounted for 91.1±0.1% and 116.4±0.2% in the reproduction mode respectively based on one lambing/year with exclusive spring control, and of 53.5±0.2% and 101.2±0.1% respectively in the traditional lambing system spread overthe year (with the ram permanently present in the flock) (P<0.05). The BCS varied according to mating season and feeding system. Indeed, as the BCS at mating increased, fertility, prolificacy and productivity improved. Ewes whose BCS at mating was equal to or greater than 3 obtained the best performance, while those with a lower BCS were less fertile, less prolific, and less productive. The average productivity of Ouled Djellal sheep was 107.0±0.1%, and 54.8±0.3%, respectively, in the first and second mode of reproduction management (P<0.05). This study highlights the main sources of variations and their interactions.

Convergent genomic signatures associated with vertebrate viviparity

BackgroundViviparity—live birth—is a complex and innovative mode of reproduction that has evolved repeatedly across the vertebrate Tree of Life. Viviparous species exhibit remarkable levels of reproductive diversity, both in the amount of care provided by the parent during gestation, and the ways in which that care is delivered. The genetic basis of viviparity has garnered increasing interest over recent years; however, such studies are often undertaken on small evolutionary timelines, and thus are not able to address changes occurring on a broader scale. Using whole genome data, we investigated the molecular basis of this innovation across the diversity of vertebrates to answer a long held question in evolutionary biology: is the evolution of convergent traits driven by convergent genomic changes?ResultsWe reveal convergent changes in protein family sizes, protein-coding regions, introns, and untranslated regions (UTRs) in a number of distantly related viviparous lineages. Specifically, we identify 15 protein families showing evidence of contraction or expansion associated with viviparity. We additionally identify elevated substitution rates in both coding and noncoding sequences in several viviparous lineages. However, we did not find any convergent changes—be it at the nucleotide or protein level—common to all viviparous lineages.ConclusionsOur results highlight the value of macroevolutionary comparative genomics in determining the genomic basis of complex evolutionary transitions. While we identify a number of convergent genomic changes that may be associated with the evolution of viviparity in vertebrates, there does not appear to be a convergent molecular signature shared by all viviparous vertebrates. Ultimately, our findings indicate that a complex trait such as viviparity likely evolves with changes occurring in multiple different pathways.