Analysis of the Evolutionary Significance of Heterosis——taking the contribution of fitness to the genetic diversity in random mating population as an example

Upon the analogy of definition of heterosis and inbreeding depresstion in terms of population genetics, the heterosis is thought to be evaluated overall with fitness. By establishing a mathematical model, the equilibrium status of three genotypes of random mating population （i. e. RR, Rr and rr） under different fitness, which exposes that heterosis is the precondition for multiallele to exist in the population. The heterosis protects the genetic diversity and makes the population owning a stronger self-control and evolution potential by improving the hetemzygote＇s fithess so as not to wash out different types of genes. It deepens Darwin＇s thoughts of individual section by making the individual fitness consonant with population fitness.

Random mating mayfly algorithm for RFID network planning

In order to improve robustness and efficiency of the radio frequency identification(RFID)network,a random mating mayfly algorithm(RMMA)was proposed.Firstly,RMMA introduced the mechanism of random mating into the mayfly algorithm(MA),which improved the population diversity and enhanced the exploration ability of the algorithm in the early stage,and find a better solution to the RFID nework planning(RNP)problem.Secondly,in RNP,tags are usually placed near the boundaries of the working space,so the minimum boundary mutation strategy was proposed to make sure the mayflies which beyond the boundary can keep the original search direction,as to enhance the ability of searching near the boundary.Lastly,in order to measure the performance of RMMA,the algorithm is then benchmarked on three well-known classic test functions,and the results are verified by a comparative study with particle swarm optimization(PSO),grey wolf optimization(GWO),and MA.The results show that the RMMA algorithm is able to provide very competitive results compared to these well-known meta-heuristics,RMMA is also applied to solve RNP problems.The performance evaluation shows that RMMA achieves higher coverage than the other three algorithms.When the number of readers is the same,RMMA can obtain lower interference and get a better load balance in each instance compared with other algorithms.RMMA can also solve RNP problem stably and efficiently when the number and position of tags change over time.

The Effect of Attendance Patterns on the Lek Mating System in the Omei Treefrog(Rhacophorus omeimontis)

Attendance patterns are a key factor affecting sexual selection and mating systems in lekbreeding species.However,there are few systematic studies on attendance patterns in lek-breeding anurans.In this study,we monitored a population of Omei treefrogs(Rhacophorus omeimontis) for four consecutive years to reveal in detail the effects of attendance patterns on mating systems.We found that(1) female nightly attendance was affected by male nightly attendance,and operational sex ratios(determined by male and female nightly attendance) ultimately determined the extent of female polyandry;(2) males surviving more than one breeding season maintained high chorus attendance and mating success,suggesting that male chorus attendance is a good predictor of male genetic quality;(3) the distributions of male mating success were not significantly different from a Poisson distribution,indicating a random mating pattern;and male mating success was not related to body size(size-assortative mating was not evident) but was significantly correlated with chorus attendance.Since the chorus attendance is a predictor of male genetic quality,females performing random mating were more likely to mate with more frequently present males and could therefore gain indirect benefits from mating with higher-than-average quality males,thereby producing good offspring without incurring the significant costs involved in prolonged searching for,and assessing males.Our systematic survey on the relationship between attendance patterns and the lek mating system in R.omeimontis could help us better understand in-depth anuran lek mating systems.

General and Exact Inbreeding Coefficient of Maize Synthetics Derived from Three-Way Line Hybrids

Synthetic varieties(SVs)are populations generated by randomly mating their parents.They are a good alternative for low-input farmers who grow onions,maize,and other allogamous crops since the seed produced by a SV does not change from one generation to the next.Although SV progenitors are commonly pure lines,in this case a synthetic(Syn_(TC))whose parents are t three-way line crosses,a very common type of maize hybrid grown in Mexico,is studied.The aim was to develop a general and exact equation for the inbreeding coefficient of a Syn_(TC)eF_(m)^(f)Syn_(TC)T because of its relationship with the mean of economically important traits.This objective arose due to the need for a more advanced study in terms of determining whether F_(m)^(f)Syn_(TC)can be applied specifically and accurately for any number of parents(t),plants per parent(m)and inbreeding coefficient(IC)of the initial lines(F_(L)).A formula for the IC of the Syn_(TC)was derived that,given any values of F_(L)(0≤F_(L)≤1)and t,is specific for any value of m,not just for“large”numbers associated with the context in which the Hardy-Weinberg law is stated.It was found that F_(m)^(f)Syn_(TC)is very sensitive to changes in m when m is not greater than eight,after which it tends to stabilize very quickly.In summary,unlike previously derived formulas,F_(m)^(f)Syn_(TC)is exact for any values of t,m and F_(L).

Asymmetrical positive assortative mating induced by developmental lead （Pb2＋） exposure in a model system, Drosophila melanogaster

Anthropogenic pollutants have the potential to disrupt reproductive strategies. Little is known about how lead （Pb2＋） exposure disrupts individual-level responses in reproductive behaviors, which are important for fitness. Drosophila melanogaster was used as a model system to deter- mine the effects of： 1） developmental lead exposure on pre-mating reproductive behaviors （i.e., mate preference）, and 2） lead exposure and mating preferences on fitness in the F0 parental generation and F1 un-exposed offspring. Wild-type strains of D. melanogaster were reared from egg stage to adulthood in control or leaded medium （250 μM PbAc） and tested for differences in： mate preference, male song performance, sex pheromone expression, fecundity, mortality, and body weight. F0 leaded females preferentially mated with leaded males （i.e., asymmetrical positive assortative mating） in 2-choice tests. This positive assortative mating was mediated by the females （and not the males） and was dependent upon context and developmental exposure to Pb. Neither the courtship song nor the sex pheromone profile expressed by control and leaded males medi- ated the positive assortative mating in leaded females. Leaded females did not incur a fitness cost in terms of reduced fecundity, increased mortality, or decreased body weight by mating with leaded males. These results suggest that sublethal exposure to lead during development can alter mate preferences in adults, but not fitness measures once lead exposure has been removed. We suggest that changes in mate preference may induce fitness costs, as well as long-term population and multi-generational implications, if pollution is persistent in the environment.