Multiplex ligation-dependant probe amplification study of children with idiopathic mental retardation in South India

BACKGROUND:

Mental retardation (MR) is a heterogeneous dysfunction of the central nervous system exhibiting complex phenotypes and has an estimated prevalence of 1-3% in the general population. However, in about 50% of the children diagnosed with any form of intellectual disability or developmental delay the cause goes undetected contributing to idiopathic intellectual disability.

MATERIALS AND METHODS:

A total of 122 children with developmental delay/MR were studied to identify the microscopic and submicroscopic chromosome rearrangements by using the conventional cytogenetics and multiplex ligation dependent probe amplification (MLPA) analysis using SALSA MLPA kits from Microbiology Research Centre Holland [MRC] Holland.

RESULTS:

All the recruited children were selected for this study, after thorough clinical assessment and metaphases prepared were analyzed by using automated karyotyping system. None was found to have chromosomal abnormality; MLPA analysis was carried out in all subjects and identified in 11 (9%) patients.

CONCLUSION:

Karyotype analysis in combination with MLPA assays for submicroscopic micro-deletions may be recommended for children with idiopathic MR.     

A stage-structured predator–prey model with distributed maturation delay and harvesting

ABSTRACT

A stage-structured predator–prey system with distributed maturation delay and harvesting is investigated. General birth and death functions are used. The local stability of each feasible equilibria is discussed. By using the persistence theory, it is proven that the system is permanent if the coexistence equilibrium exists. By using Lyapunov functional and LaSalle invariant principle, it is shown that the trivial equilibrium is globally stable when the other equilibria are not feasible, and that the boundary equilibrium is globally stable if the coexistence equilibrium does not exist. Finally, sufficient conditions are derived for the global stability of the coexistence equilibrium.     

Phase response curve to 1 h light pulses for the European rabbit (Oryctolagus cuniculus)

While much is known about the circadian systems of rodents, chronobiological studies of other mammalian groups have been limited. One of the most extensively studied nonrodent species, both in the laboratory and in the wild, is the European rabbit. The aim of this study was to extend knowledge of the rabbit circadian system by examining its phasic response to light. Twelve Dutch-Himalayan cross rabbits of both sexes were allowed to free-run in constant darkness and then administered 1 h light pulses (1000 lux) at multiple predetermined circadian times. Changes in the phase of the rabbits’ circadian wheel-running rhythms were measured after each light pulse and used to construct a phase–response curve (PRC). The rabbits’ PRC and free-running period (τ) conformed to the empirical regularities reported for other predominantly nocturnal animals, including rodents and predatory marsupials. The results of the study are thus consistent with reports that the rabbit is essentially a nocturnal animal and show that it can entrain to light/dark (LD) cycles via discrete phase shifts. Knowledge about the rabbit’s circadian range of entrainment to LD cycles gained in this study will be useful for examining the putative circadian processes believed to underlie the unusual rhythm of very brief, once-daily nest visits by nursing rabbit mothers and other nursing lagomorphs.     

Economic weights of maternal and direct traits of pigs calculated by applying gene flow methods

Multiple trait selection indexes in pig breeding programmes should take into account the population structure and time delay between parent selection and expressions of traits in all production levels next to the trait impacts on economic efficiency of production systems. Gene flow procedures could be used for the correct evaluation of maternal and direct traits of pig breeds involved in breeding or crossbreeding systems. Therefore, the aim of this study was to expand a previously developed bioeconomic model and computer program to calculate the marginal economic values by including a gene flow procedure to calculate the economic weights for maternal and direct traits in pig breeds. The new program was then applied to the three-way crossbreeding system of the Czech National Programme for Pig Breeding. Using this program, the marginal economic values of traits for dam breeds Czech Large White in the dam position and Czech Landrace in the sire position, and for the sire breed Pietrain were weighted by the number of discounted gene expressions of selected parents of each breed summarised within all links of the crossbreeding system during the 8-year investment period. Economic weights calculated in this way were compared with the approximate economic weights calculated previously without a gene flow procedure. Taking into account the time delay between parent selection and trait expression (using discounting with half-year discount rates of 2% or 5%) and including more than one generation of parent progeny had little impact on the relative economic importance of maternal and direct traits of breeds involved in the evaluated three-way crossbreeding system. These results indicated that this gene-flow method could be foregone when estimating the relative economic weights of traits in pig crossbreeding systems applying artificial insemination at all production levels.