scholarly journals Genetic basis of body color and spotting pattern in redheaded pine sawfly larvae (Neodiprion lecontei)

2017 ◽  
Author(s):  
Catherine R. Linnen ◽  
Claire T. O’Quin ◽  
Taylor Shackleford ◽  
Connor R. Sears ◽  
Carita Lindstedt

ABSTRACTPigmentation has emerged as a premier model for understanding the genetic basis of phenotypic evolution, and a growing catalog of color loci is starting to reveal biases in the mutations, genes, and genetic architectures underlying color variation in the wild. However, existing studies have sampled a limited subset of taxa, color traits, and developmental stages. To expand our sample of color loci, we performed quantitative trait locus (QTL) mapping analyses on two types of larval pigmentation traits that vary among populations of the redheaded pine sawfly (Neodiprion lecontei): carotenoid-based yellow body color and melanin-based spotting pattern. For both traits, our QTL models explained a substantial proportion of phenotypic variation and suggested a genetic architecture that is neither monogenic nor highly polygenic. Additionally, we used our linkage map to anchor the current N. lecontei genome assembly. With these data, we identified promising candidate genes underlying: (1) a loss of yellow pigmentation in Mid-Atlantic/northeastern populations (Cameo2 and apoLTP-II/I), and (2) a pronounced reduction in black spotting in Great-Lakes populations (yellow, TH, Dat). Several of these genes also contribute to color variation in other wild and domesticated taxa. Overall, our findings are consistent with the hypothesis that predictable genes of large-effect contribute to color evolution in nature.


Genetics ◽  
2018 ◽  
Vol 209 (1) ◽  
pp. 291-305 ◽  
Author(s):  
Catherine R. Linnen ◽  
Claire T. O’Quin ◽  
Taylor Shackleford ◽  
Connor R. Sears ◽  
Carita Lindstedt


Author(s):  
Abigail M. Lamb ◽  
Zinan Wang ◽  
Patricia Simmer ◽  
Henry Chung ◽  
Patricia J. Wittkopp

1AbstractDrosophila pigmentation has been a fruitful model system for understanding the genetic and developmental mechanisms underlying phenotypic evolution. For example, prior work has shown that divergence of the tan gene contributes to pigmentation differences between two members of the virilis group: Drosophila novamexicana, which has a light yellow body color, and D. americana, which has a dark brown body color. Quantitative trait locus (QTL) mapping and expression analysis has suggested that divergence of the ebony gene might also contribute to pigmentation differences between these two species. Here, we directly test this hypothesis by using CRISPR/Cas9 genome editing to generate ebony null mutants in D. americana and D. novamexicana and then using reciprocal hemizygosity testing to compare the effects of each species’ ebony allele on pigmentation. We find that divergence of ebony does indeed contribute to the pigmentation divergence between species, with effects on both the overall body color as well as a difference in pigmentation along the dorsal abdominal midline. Motivated by recent work in D. melanogaster, we also used the ebony null mutants to test for effects of ebony on cuticular hydrocarbon (CHC) profiles. We found that ebony affects CHC abundance in both species, but does not contribute to qualitative differences in the CHC profiles between these two species. Additional transgenic resources for working with D. americana and D. novamexicana, such as white mutants of both species and yellow mutants in D. novamexicana, were generated in the course of this work and are also described. Taken together, this study advances our understanding of loci contributing to phenotypic divergence and illustrates how the latest genome editing tools can be used for functional testing in non-model species.



2012 ◽  
Vol 90 (5) ◽  
pp. 564-576 ◽  
Author(s):  
Ravi Parkash ◽  
Seema Ramniwas ◽  
Babita Kajla

In the fruit fly Drosophila melanogaster Meigen, 1830, abdominal melanisation varies in a quantitative manner, but little attention has been paid to the genetic basis of different phenotypic classes and their ecological significance in the wild populations. Laboratory-selected darker and lighter body color strains were used for determining the genetic basis of body color phenotypes. Based on such genetic characterization, we interpreted body color variation of wild flies collected along a latitudinal gradient. Our results are interesting in several respects. First, laboratory selection produced lighter females and also lighter males, in contradiction of the well-known sexual dimorphism in D. melanogaster. The laboratory-selected darker and lighter strains showed lack of phenotypic plasticity, whereas F1 flies from reciprocal crosses showed significant levels of phenotypic plasticity. Second, for both sexes, F2 phenotypic classes resulting from reciprocal crosses between selected darker and lighter strains fit a two-locus model with a stronger maternal effect in males than in females. Third, changes in continuously varying abdominal melanisation of wild-caught flies were sorted into phenotypic bins of body color phenotypic classes and such data on geographical populations of D. melanogaster are consistent with climatic selection. Thus, we may suggest that for ecological genetic studies, greater emphasis should be laid on the analysis of bins of phenotypic classes of body melanisation in laboratory and wild populations of D. melanogaster.



2002 ◽  
Vol 11 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Brenda K. Smith Richards ◽  
Brenda N. Belton ◽  
Angela C. Poole ◽  
James J. Mancuso ◽  
Gary A. Churchill ◽  
...  

The present study investigated the inheritance of dietary fat, carbohydrate, and kilocalorie intake traits in an F2 population derived from an intercross between C57BL/6J (fat-preferring) and CAST/EiJ (carbohydrate-preferring) mice. Mice were phenotyped for self-selected food intake in a paradigm which provided for 10 days a choice between two macronutrient diets containing 78/22% of energy as a composite of either fat/protein or carbohydrate/protein. Quantitative trait locus (QTL) analysis identified six significant loci for macronutrient intake: three for fat intake on chromosomes (Chrs) 8 ( Mnif1), 18 ( Mnif2), and X ( Mnif3), and three for carbohydrate intake on Chrs 17 ( Mnic1), 6 ( Mnic2), and X ( Mnic3). An absence of interactions among these QTL suggests the existence of separate mechanisms controlling the intake of fat and carbohydrate. Two significant QTL for cumulative kilocalorie intake, adjusted for baseline body weight, were found on Chrs 17 ( Kcal1) and 18 ( Kcal2). Without body weight adjustment, another significant kcal locus appeared on distal Chr 2 ( Kcal3). These macronutrient and kilocalorie QTL, with the exception of loci on Chrs 8 and X, encompassed chromosomal regions influencing body weight gain and adiposity in this F2 population. These results provide new insight into the genetic basis of naturally occurring variation in nutrient intake phenotypes.



2021 ◽  
Author(s):  
Kim Vertacnik ◽  
Danielle Herrig ◽  
R Keating Godfrey ◽  
Tom Hill ◽  
Scott Geib ◽  
...  

A central goal in evolutionary biology is to determine the predictability of adaptive genetic changes. Despite many documented cases of convergent evolution at individual loci, little is known about the repeatability of gene family expansions and contractions. To address this void, we examined gene family evolution in the redheaded pine sawfly Neodiprion lecontei, a non-eusocial hymenopteran and exemplar of a pine-specialized lineage evolved from angiosperm-feeding ancestors. After assembling and annotating a draft genome, we manually annotated multiple gene families with chemosensory, detoxification, or immunity functions and characterized their genomic distributions and evolutionary history. Our results suggest that expansions of bitter gustatory receptor (GR), clan 3 cytochrome P450 (CYP3), and antimicrobial peptide (AMP) subfamilies may have contributed to pine adaptation. By contrast, there was no evidence of recent gene family contraction via pseudogenization. Next, we compared the number of genes in these same families across insect taxa that vary in diet, dietary specialization, and social behavior. In Hymenoptera, herbivory was associated with large GR and small olfactory receptor (OR) families, eusociality was associated with large OR and small AMP families, and--unlike investigations among more closely related taxa--ecological specialization was not related to gene family size. Overall, our results suggest that gene families that mediate ecological interactions may expand and contract predictably in response to particular selection pressures, however, the ecological drivers and temporal pace of gene gain and loss likely varies considerably across gene families.



Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 751-764 ◽  
Author(s):  
H. Tsukaya ◽  
S. Naito ◽  
G. P. Redei ◽  
Y. Komeda

We isolated and analyzed mutants of Arabidopsis thaliana, acaulis, with flower stalks that are almost absent or are much reduced in length. The mutations are divided between two loci, acaulis1 (acl1) and acaulis2 (acl2). The acl1-1 mutation has been assigned to linkage group 4 in the vicinity of locus ap2. The acl1-1 mutant showed premature arrest of the inflorescence meristem after the onset of reproductive development, followed by consequent reduction in the number of flower-bearing phytomers and therefore flowers. The apical meristem of the inflorescences was morphologically normal but its radius was about half that of the wild type. The acl1 mutants are also defective in the development of foliage leaves. Both defects could be rescued by growth at a specific temperature (28°C). The length of the cells in acl1-3 mutant was less than that in the wild type but the numbers of cells in leaves and internodes of acl1 mutants were calculated to be the same as those of the wild type. Thus, the defects in inflorescences and leaves were attributed to defects in the process of elongation (maturation) of these cells. Temperature-shift experiments showed that the Acl1+ product was necessary at all developmental stages. A critical stage was shown to exist for recovery from the cessation of development of inflorescence meristems that was caused by the acl1-1 mutation. Grafting experiments showed that the acl1-1 mutation does not affect diffusible substances. An analysis of double mutants carrying both acl1-1 and one of developmental mutations, ap1, clv1, lfy, or tfl1, showed that ACL1 is a new class of gene.



2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carolina Ballén-Taborda ◽  
Ye Chu ◽  
Peggy Ozias-Akins ◽  
Patricia Timper ◽  
C. Corley Holbrook ◽  
...  

AbstractRoot-knot nematode is a very destructive pathogen, to which most peanut cultivars are highly susceptible. Strong resistance is present in the wild diploid peanut relatives. Previously, QTLs controlling nematode resistance were identified on chromosomes A02, A04 and A09 of Arachis stenosperma. Here, to study the inheritance of these resistance alleles within the genetic background of tetraploid peanut, an F2 population was developed from a cross between peanut and an induced allotetraploid that incorporated A. stenosperma, [Arachis batizocoi x A. stenosperma]4×. This population was genotyped using a SNP array and phenotyped for nematode resistance. QTL analysis allowed us to verify the major-effect QTL on chromosome A02 and a secondary QTL on A09, each contributing to a percentage reduction in nematode multiplication up to 98.2%. These were validated in selected F2:3 lines. The genome location of the large-effect QTL on A02 is rich in genes encoding TIR-NBS-LRR protein domains that are involved in plant defenses. We conclude that the strong resistance to RKN, derived from the diploid A. stenosperma, is transferrable and expressed in tetraploid peanut. Currently it is being used in breeding programs for introgressing a new source of nematode resistance and to widen the genetic basis of agronomically adapted peanut lines.



Zootaxa ◽  
2011 ◽  
Vol 3046 (1) ◽  
pp. 39 ◽  
Author(s):  
William F. SMITH-VANIZ ◽  
GERALD R. ALLEN

Three new species of fangblennies are described from Indonesia. Meiacanthus abruptus is described based on two specimens, 31.4–36.6 mm SL, from Komodo Island and color photographs of others from Bali. The combination of a white or yellow body color and a single dark mid-lateral stripe that is bluntly rounded at its terminus on the caudal-fin base distinguishes it from other single striped species. This new species closely resembles the allopatric M. vicinus, which has the mid-lateral stripe extending farther onto the caudal fin and tapering to a point. Meiacanthus erdmanni is described from the only known specimen, 35.8 mm SL, photographed and collected in 65–70 m in Cenderawasih Bay, western New Guinea. One of the deepest known species of Meiacanthus, it has two dark mid-lateral stripes and differs from other doublestriped species in having a series of dark blotches on the base of the dorsal fin and only 24 segmented dorsal-fin rays. Meiacanthus cyanopterus, another deep-water species, is described from seven specimens, 19.8–45.3 mm SL, collected in 40–65 m at three sites in Alor Strait. In life this species has a dorsal fin with a blue-violet stripe bordered above by a wide black stripe. An identification key is provided for all the striped species of Meiacanthus, including at least one additional undescribed species previously confused with M. abditus. Color photographs of other Meiacanthus species and some new distributional records are also given.



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