The significance of purine base content as an important nutrition indicator in foods arises from its potential to trigger hyperuricemia or gout via high-purine diet.  Livestock meats, including pork, generally contain moderate to high total purine content (TP).  Recent research revealed substantial variations within and across pig breeds, implying genetic factors influencing this trait.  Thus, this study aimed to unravel the genetic underpinnings governing purine base content in pork.  The heritability estimates (h²) for the four purine traits ranged from 0.14 to 0.35.  A total of 14, 36, 19 and 25 quantitative trait loci (QTLs) were identified for guanine, adenine, hypoxanthine, and TP, respectively.  Our comprehensive gene set enrichment analysis and gene network analysis revealed 15 promising candidate genes intricately interwoven within diverse purine metabolism pathways, such as purine ribonucleotide metabolic process, purine nucleotide metabolism and transport, and purine salvage pathways, all contributing to TP.  Strikingly, most genetic variants significantly associated with TP displayed analogous effects on multiple purine bases.  Two distinct and highly significant QTLs (P<10^–12) emerged on Sus scrofa chromosome (SSC) 12: one impacting guanine content and the other concurrently influencing adenine and hypoxanthine levels.  The peak of the guanine QTL on SSC12 resided 1.1 kb downstream of the transmembrane protein 238 like (TMEM238L) gene and is encapsulated within a genomic segment characterized by the histone modification H3K27me3.  Focused fine-mapping for the SSC12 QTL associated with adenine and hypoxanthine levels narrowed its scope to around 172 kb, encompassing the growth arrest specific 7 (GAS7) and myosin heavy chain 13 (MYH13) genes.  However, the observed QTL effect was not attributed to any missense mutations within the two genes.  This pioneering study unveils the genetic variations and candidate genes associated with purine content in livestock, laying a robust foundation for the selective breeding of pig lines with reduced purine base content.

The native thelytokous (TH) and arrhenotokous (AR) strains of Neochrysocharis formosa (Westwood) (Hymenoptera: Eulophidae) are promising biocontrol agents against the invasive tomato pest Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae).  This study assessed the performance and preferences of these strains in choice experiments involving five host instar ratios and evaluated their functional responses to seven densities of 1st instar larvae (5 to 40 hosts).  In host-attacking behavior assays, an increasing proportion of 1st instar larvae led to a significant rise in host mortality rates for both strains.  Both strains exhibited strong preferences for parasitizing and attacking 1st instar larvae over later instars, with the TH strain demonstrating significantly greater host-killing efficacy than the AR strain.  Functional response experiments revealed that the attack rates of both strains were positively correlated with host density.  Parasitism by both strains and host-stinging behavior by the TH strain showed type III functional responses, while host-feeding by both strains and host-stinging by the AR strain followed type II functional responses.  Early establishment of the TH strain in tomato agroecosystems could enhance the management of T. absoluta.  These findings provide critical insights into the functional dynamics of the TH and AR strains of N. formosa that can inform the development of effective biocontrol programs for this globally significant pest.