Testing the potential mechanisms for the maintenance of a genetic color polymorphism in bluefin killifish populations

The maintenance of genetic variation in the face of natural selection is a long-standing question in evolutionary biology.In the bluefin killifish Lucania goodei,male coloration is polymorphic.Males can produce either red or yellow coloration in their anal fins,and both color morphs are present in all springs.These 2 morphs are heritable and how they are maintained in nature is unknown.Here, we tested 2 mechanisms for the maintenance of the red/yellow color morphs.Negative frequency-dependent mating success predicts that rare males have a mating advantage over common males. Spatial variation in fitness predicts that different color morphs have an advantage in different microhabitat types.Using a breeding experiment,we tested these hypotheses by creating populations with different ratios of red to yellow males (5 red:1 yellow;1 red:5 yellow)and determining male mating success on shallow and deep spawning substrates.We found no evidence of negative frequency-dependent mating success.Common morphs tended to have higher mating success, and this was particularly so on shallow spawning substrates.However,on deep substrates,red males enjoyed higher mating success than yellow males,particularly so when red males were rare. However,yellow males did not have an advantage at either depth nor when rare.We suggest that preference for red males is expressed in deeper water,possibly due to alterations in the lighting environment.Finally,male pigment levels were correlated with one another and predicted male mating success.Hence,pigmentation plays an important role in male mating success.

Application of isoxanthopterin as a new pterin marker in the differential diagnosis of hyperphenylalaninemia

Background This study aimed to explore the value of applying a new pterin marker (isoxanthopterin) to the traditional urine pterin analysis to reduce the rate of mis-diagnosis of 6-pyruvoyltetrahydropterin synthase deficiency (PTPSD) and improve the accuracy of diagnosis.Methods We compared the urine neopterin (N),biopterin (B),isoxanthopterin (Iso),B% and Iso% levels between patients with phenylalanine hydroxylase deficiency and those with PTPSD,and found the most specific pterin biomarkers by ROC analysis.A positive cut-off value of urine pterins was determined.The effect of combined Iso% + B + B% in reducing PTPSD mis-diagnosis was evaluated,and the different urine pterin levels in PTPSD and false PTPSD (FPTPSD) were compared.The concordance of PTPSD diagnosis by the new pterin scheme and gene mutation analysis was determined.Results (1) Urinary B,B%,Iso and Iso% were significantly lower in PTPSD than those in phenylalanine hydroxylase-deficiency group (P < 0.01);(2) Iso%,B%,and B were the most specific markers;(3) The positive cut-off values of B,B%,Iso% for PTPSD were < 0.17 mmoL/moLCr,< 5.0%,and < 9.5%,respectively;(4) urinary B +B% + Iso% scheme significantly reduced the false-positive rate of PTPSD compared to traditional ones.The Iso% levels in FPTPSD group were higher than the ones in PTPSD group;(5) an accuracy of diagnosis for PTPSD was increased by 9-19% when Iso% was introduced to urinary pterin scheme.Conclusions Iso% is helpful to reduce the rate of misdiagnosis of PTPSD in the diagnosis by urinary pterin analysis for hyperphenylalaninemias and improve the accuracy of diagnosis.This approach is worthy of further development and increased utilization.