Unraveling genetics of semi-determinacy and identification of markers for indeterminate stem growth habit in chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is predominantly an indeterminate plant and tends to generate vegetative growth when the ambient is conducive for soil moisture, temperature and certain other environmental conditions. The semi-determinate (SDT) types are comparatively early, resistant to lodging and found to be similar in their yield potential to indeterminate (IDT) lines. Indeterminate and semi-determinate genotypes are found to be similar during early stage, which makes it difficult to distinguish between them. Thus, there is a need to identify molecular markers linked either to indeterminate or semi-determinate plant types. The present study was carried out to study the genetics of semi-determinacy and identify molecular markers linked to stem growth habit. The study was undertaken in the cross involving BG 362(IDT) × BG 3078-1(SDT). All F1 plants were indeterminate, which indicates that indeterminate stem type is dominant over semi-determinate. In further advancement to F2 generation, F2 plants are segregated in the ratio of 3(Indeterminate): 1(Semi-determinate) that indicates that the IDT and SDT parents which are involved in the cross differed for a single gene. The segregation pattern observed in F2 is confirmed in F3 generation. The parental polymorphic survey was undertaken for molecular analysis using total of 245 SSR markers, out of which 41 polymorphic markers were found to distinguish the parents and were utilized for bulked segregant analysis (BSA). The segregation pattern in F2 indicates that the IDT (Indeterminate) and SDT (Semi-determinate) parents which are involved in the cross differed for single gene. The segregation pattern of F2 and F3 derived from the cross BG 362 (IDT) × BG 3078-1 (SDT) confirmed the genotypic structure of the newly found SDT genotype BG 3078-1 as dt1dt1Dt2Dt2. Three SSR markers TA42, Ca_GPSSR00560 and H3DO5 were found to be putatively linked to Dt1 locus regulating IDT stem growth habit. Our results indicate that the SSR markers identified for Dt1 locus helps to differentiate stem growth habit of chickpea in its early growth stage itself and can be efficiently utilized in Marker Assisted Selection (MAS) for changed plant type in chickpea.

P–083 Analysis of chromosomal segregation and interchromosomal effects (ICE) in sperms from balanced translocation carriers using fluorescence in situ hybridization (FISH) after sperm selector separation

Study question Influence of sperm selector separation of sperms on their translocation load, segregation pattern, motility and occurrence of interchromosomal effects Summary answer Sperm selector separation led to reduction of the translocation load, shift in segregation pattern and lower rates of interchromosomal effects within sperm samples What is known already Balanced translocations in men are known to be one of the main causes of reproductive failure. The segregation pattern in sperms is determined by the distribution of the chromosomes during meiosis. Interchromosomal effects can also influence the distribution of chromosomes that are not involved in the translocation. The sperm selector used consists of two concentric chambers, which are overlaid by a U-ring and a cover glass. Motile sperms migrate from the native ejaculate in the medium filled inner chamber by using a capillary bridge created by the U-ring. This avoids potential harmful centrifugation and allows accumulation of motile sperms. Study design, size, duration Twenty-one carriers of balanced translocations participated in the study. In addition, 15 patients were involved as control. All participants signed an informed consent (F–8–15). Samples of three patients did not meet the internal quality criteria and had to be excluded from analysis. The study started in 2015 and is still ongoing. Participants/materials, setting, methods Liquefied native ejaculate was processed with a sperm selector. Native ejaculate, non-migrated sperms from the outer chamber and migrated sperms from the inner chamber were transferred onto glass slides, fixed and underwent a decondensation treatment. For segregation analysis FISH translocation specific FISH probe mixes were used and tested on patient’s blood. Interchromosomal effects were analysed with FISH probes for the chromosomes X, Y, 18 and 13, 21. Evaluation was done manually using fluorescence microscopy. Main results and the role of chance Segregation analysis was done for more than 25,000 sperms from men carrying a balanced translocation (18 patients with reciprocal and 3 patients with Robertsonian translocation). Separation via sperm selector led to a reduction in translocation load (native to separated approach 49,1±11,5% to 34,8±9,4% (P = <0,01), the rate depending on the specific translocation. There was also a shift in the segregation pattern, which seemed to be influenced by the specific translocation and the resulting steric alignment of the corresponding quadrivalent / trivalent. Additionally, more than 90,000 sperms from patients with balanced translocations were analysed for interchromosomal effects. Separation led to reduced maldistribution rate (native to separated approach 7,1±3,5% to 5±3,1%, P = <0,01) whereas the steric alignment of the corresponding quadrivalent / trivalent seems to influence the interchromosomal effect as well. For control, sperms from control patients were analysed regarding the chromosomes X, Y, 18 and 13, 21. In about 90,000 control sperms separation led to reduced maldistribution rate (native to separated approach 5,4±1,5% to 3,8±1,1%; P = <0,01). Limitations, reasons for caution The number of accumulated strandbreak-free sperms depended on the motility and sperm count of the native ejaculate. Examinations are not reproducible, as each sample delivery is influenced by external circumstances Wider implications of the findings: Sperm selector separation can be used before ART to reduce the translocation load and rate of maldistribution in sperms from carriers of balanced translocations. This could have a considerable impact on PGT results after trophectoderm biops. Trial registration number Not applicable

Unraveling Genetics of Semi-Determinancy and Identification of Markers for Indeterminate Stem Growth Habit in Chickpea (Cicer Arietinum L.)

BackgroundChickpea (Cicer arietinum L.) is predominantly an indeterminate plant and tends to generate vegetative growth when the ambient is conducive for soil moisture, temperature and certain other environmental conditions. The semi-determinate (SDT) types are comparatively early, resistant to lodging and found to be similar in their yield potential to indeterminate (IDT) lines. Indeterminate types and semi-determinate genotypes are found to be similar during early stage, which makes it difficult to distinguish between them. Thus, there is a need to identify molecular marker linked either to indeterminate or semi-determinate plant type. The present study was carried out to study the genetics of semi-determinacy and identify molecular markers linked to stem growth habit. MethodsThe study was undertaken in the cross involving BG 362(IDT) X BG 3078-1(SDT). All F1 plants were indeterminate, which indicates that indeterminate stem type is dominant over semi-determinate. In further advancement to F2 generation, F2 plants are segregated in the ratio of 3(Indeterminate): 1(Semi-determinate) that indicates that the IDT and SDT parents which are involved in the cross differed for a single gene. The segregation pattern observed in F2 is confirmed in F3 generation. The parental polymorphic survey was undertaken for molecular analysis using total of 246 SSR markers, out of which 41 polymorphic markers were found to distinguish the parents and were utilized for bulked segregant analysis (BSA). ResultsThe segregation pattern in F2 indicates that the IDT(Indeterminate) and SDT(Semi-determinate) parents which are involved in the cross differed for single gene. The segregation pattern of F2 and F3 derived from the cross BG 362 (IDT) x BG 3078-1 (SDT) confirmed the genotypic structure of the newly found SDT genotype BG 3078-1 as dt1dt1Dt2Dt2. Three SSR markers TA42, Ca_GPSSR00560 and H3DO5 were found to be putatively linked to Dt1 locus regulating IDT stem growth habit.ConclusionOur results indicate that the SSR markers identified for Dt1 locus helps to differentiate stem growth habit of chickpea in its early growth stage itself and can be efficiently utilized in Marker Assisted Selection (MAS) for changed plant type in chickpea.

Meiotic Heterogeneity of Trivalent Structure and Interchromosomal Effect in Blastocysts With Robertsonian Translocations

BackgroundRobertsonian translocations are common structural rearrangements and confer an increased genetic reproductive risk due to the formation of trivalent structure during meiosis. Studies on trivalent structure show meiotic heterogeneity between different translocation carriers, although the factors causing heterogeneity have not been well elaborated in blastocysts. It is also not yet known whether interchromosomal effect (ICE) phenomenon occurs in comparison with suitable non-translocation control patients. Herein, we aimed to evaluate the factors that cause meiotic heterogeneity of trivalent structure and the ICE phenomenon.MethodsWe designed a retrospective study, comprising 217 Robertsonian translocation carriers and 134 patients with the risk of transmitting monogenic inherited disorders (RTMIDs) that underwent preimplantation genetic testing (PGT). Data was collected between March 2014 and December 2019. The segregation products of trivalent structure were analyzed based on the carrier’s gender, age and translocation type. In addition, to analyze ICE phenomenon, aneuploidy abnormalities of non-translocation chromosomes from Robertsonian translocation carriers were compared with those from patients with RTMIDs.ResultsWe found that the percentage of male carriers with alternate segregation pattern was significantly higher [P < 0.001, odds ratio (OR) = 2.95] than that in female carriers, while the percentage of adjacent segregation pattern was lower (P < 0.001, OR = 0.33). By contrast, no difference was observed between young and older carriers when performing stratified analysis by age. Furthermore, segregation pattern was associated with the D;G chromosomes involved in Robertsonian translocation: the rate of alternate segregation pattern in Rob(13;14) carriers was significantly higher (P = 0.010, OR = 1.74) than that in Rob(14;21) carriers, whereas the rate of adjacent segregation pattern was lower (P = 0.032, OR = 0.63). Moreover, the results revealed that the trivalent structure could significantly increase the frequencies of chromosome aneuploidies 1.30 times in Robertsonian translocation carriers compared with patients with RTMIDs (P = 0.026), especially for the male and young subgroups (P = 0.030, OR = 1.35 and P = 0.012, OR = 1.40), while the mosaic aneuploidy abnormalities presented no statistical difference.ConclusionsOur study demonstrated that meiotic segregation heterogeneity of trivalent structure is associated with the carrier’s gender and translocation type, and it is independent of carrier’s age. ICE phenomenon exists during meiosis and then increases the frequencies of additional chromosome abnormalities.

Pola Segregasi Sifat Ketahanan Terhadap Soybean Stunt Virus dan Keragaman Genetik FAMILI F2:3 HASIL PERSILANGAN VARIETAS ORBA DAN GALUR B3570

Segregation pattern of the Soybean Stunt Virus resistant character and genetic diversity of F2:3 families derived from crosses between Orba and B3570. Soybean stunt disease caused by SSV (Soybean Stunt Virus) is the most destructive soybean disease in Indonesia. This research was conducted from October 2005 to June 2006 at experiment station of Lampung University. The aims of this research were to evaluate the segregation of resistant characters and total genetic diversity of eight populations of F2:3 families. Experiment was arranged in a randomized complete block design with three replications. The resistance was evaluated based on the score of disease severity. The results showed that the resistant characters segregate 1:2:1 to susceptible, moderately resistant, and resistant, respectively based on the segregation pattern. The resistant character was controlled by single gene and the action of the gene is noncompletely dominant gene. Eight populations of F2:3 families have high diversities on the yield and yield components.

Mirrored brain organization: Statistical anomaly or reversal of hemispheric functional segregation bias?

Humans demonstrate a prototypical hemispheric functional segregation pattern, with language and praxis lateralizing to the left hemisphere and spatial attention, face recognition, and emotional prosody to the right hemisphere. In this study, we used fMRI to determine laterality for all five functions in each participant. Crucially, we recruited a sample of left-handers preselected for atypical (right) language dominance (n= 24), which allowed us to characterize hemispheric asymmetry of the other functions and compare their functional segregation pattern with that of left-handers showing typical language dominance (n= 39). Our results revealed that most participants with left language dominance display the prototypical pattern of functional hemispheric segregation (44%) or deviate from this pattern in only one function (35%). Similarly, the vast majority of right language dominant participants demonstrated a completely mirrored brain organization (50%) or a reversal for all but one cognitive function (32%). Participants deviating by more than one function from the standard segregation pattern showed poorer cognitive performance, in line with an oft-presumed biological advantage of hemispheric functional segregation.

Unexpected segregation patterns in high speed granular flows

<p align="JUSTIFY">Classically, for free surface flows of binary granular mixture, large particles migrate at the top of the flow while small ones percolate to the bottom. The key mechanisms at the origin of this segregation behavior have been identified as a combination of squeeze expulsion and kinetic sieving (Savage & Lun J. Fluid Mech. 1988). In this case, the segregation process is governed by the gravity. We <span>discovered</span> here by means of numerical simulations a new segregation pattern in high speed granular flows where size segregation is driven mostly by granular temperature gradients rather than gravity, which highlight the complexity of providing a complete description of segregation processes.</p><p align="JUSTIFY">High speed granular flows are obtained by means of discrete numerical simulations (DEM) in a confined geometry with lateral frictional side-walls. Recently, Brodu et al. (Phys. Rev. E 2013, J. Fluid Mech. 2015) highlighted that this confined geometry allows to produce steady and fully-developed flows at relatively high angles of inclination, including a rich and broad variety of new regimes. In particular, they showed the existence of supported regimes, characterized by a dense and cold (in terms of granular temperature) core floating over a dilute and highly agitated layer of grains, accompanied with longitudinal convection rolls.</p><p align="JUSTIFY">We performed extensive numerical simulations within this geometry with binary mixture of spheres with a given size ratio of 2. We analyzed segregation patterns of steady and fully-developed flows for inclination angles ranging from 18° to 50° and various mixture proportions of large particles ranging from 0 to 100%. We evidenced a new segregation pattern that emerge in the supported flow regimes: large particles no longer accumulate in the upper layers of the flow but are trapped in the dense core and localized at the center of the convection rolls. The strong temperature gradients that develop between the dense core and the surrounding dilute layer seem to govern the segregation mechanism. The accumulation of large particles in the dense core, which is the fastest region of the flow, also tends to enhance the total mass flux in comparison with similar mono-disperse flows.</p>

On the generation and segregation of helicity in geodynamo simulations

SUMMARY Helicity, the inner product of velocity and vorticity, is considered an important ingredient for the maintenance of a dipolar magnetic field in the geodynamo. Outside the tangent cylinder—an imaginary cylinder which circumscribes the inner core—a spatial segregation of helicity has been observed in several simulations, being negative in the north and positive in the south. Such a segregation pattern is important for a dynamo that relies on the α-effect. However, the origin of this pattern in these simulations is poorly understood. In this paper, we use three strongly forced numerical dynamo solutions to study the various sources of helicity, including those due to buoyancy $({H_T})$, Coriolis, Lorentz and viscous forces. We find a strong spatial correlation between the segregation pattern of helicity and ${H_T}$ both in the instantaneous and the time-averaged results. Our results show that, outside the tangent cylinder, ${H_T}$ is dominated by the product $- {u_z}\partial T/\partial \varphi $, where ${u_z}$ is the vertical velocity component and T is the temperature perturbation. It is known that when inertial waves are launched from a localized buoyant anomaly, ${H_T}$ takes the same sign as the local helicity. We conjecture that this is the reason for the spatial correlation between ${H_T}$ and helicity in our simulation results. The flow in our simulations being strongly turbulent, this effect seems to be a statistical one and manifests itself most clearly in the averaged quantities.