scholarly journals Different molecular changes underlie the same phenotypic transition: origins and consequences of independent shifts to homostyly within species

2021 ◽  
Author(s):  
Emiliano Mora-Carrera ◽  
Rebecca Stubbs ◽  
Barbara Keller ◽  
Étienne Léveillé-Bourret ◽  
Jurriaan de Vos ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Prime Model ◽  
Loss Of Function ◽  
Different Types ◽  
Inbreeding Level ◽  
Floral Morph ◽  
Phenotypic Transition ◽  
Phenotypic Convergence

The molecular basis of phenotypic convergence, a key topic in evolutionary biology and ecology, has been investigated especially between species. However, it remains unclear whether mutations in the same or different positions of the same gene, or in different genes underlie phenotypic convergence within species. A classic example of convergence is the transition from outcrossing to selfing in plants, illustrated by the repeated shift from heterostyly to homostyly. Heterostyly is characterized by the reciprocal position of male and female sexual organs in two (or three) distinct, incompatible floral morphs, while homostyly is characterized by a single, self-compatible floral morph. Primula has long served as the prime model for studies of heterostyly and homostyly. Here, we elucidate the phenotypic and molecular origins of homostyly in P. vulgaris and its microevolutionary consequences by integrating microsatellite analyses of both progeny arrays and natural populations characterized by varying frequencies of homostyles with DNA sequence analyses of the gene controlling the position of female sexual organs (CYPᵀ). We found that: homostyles evolved repeatedly from short-styled individuals in association with different types of loss-of-function mutations in CYPᵀ and, consequently, short-styled individuals occur at lower frequencies than long-styled individuals across populations with all three morphs; the shift to homostyly promotes a shift to selfing; and intra-population frequency of homostyles is positively correlated with selfing rate and inbreeding level, increasing genetic differentiation among populations. These results elucidate the connections between the genotypic and phenotypic levels of convergence and the effects of contrasting floral morphologies on reproductive strategies.

scholarly journals Different molecular changes underlie the same phenotypic transition: origins and consequences of independent shifts to homostyly within species

2021 ◽  
Author(s):  
Emiliano Mora-Carrera ◽  
Rebecca Stubbs ◽  
Barbara Keller ◽  
Étienne Léveillé-Bourret ◽  
Jurriaan de Vos ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Natural Populations ◽  
Loss Of Function ◽  
Low Frequencies ◽  
Male And Female ◽  
Primula Vulgaris ◽  
System Transition ◽  
Different Types ◽  
Floral Morph ◽  
Phenotypic Transition

The repeated transition from outcrossing to selfing is a key topic in evolutionary biology. However, the molecular basis of such shifts has been rarely examined due to lack of knowledge of the genes controlling these transitions. A classic example of mating system transition is the repeated shift from heterostyly to homostyly. Occurring in 28 angiosperm families, heterostyly is characterized by the reciprocal position of male and female sexual organs in two (or three) distinct, usually self-incompatible floral morphs. Conversely, homostyly is characterized by a single, self-compatible floral morph with reduced separation of male and female organs, facilitating selfing. Here, we investigate the origins of homostyly in Primula vulgaris and its microevolutionary consequences by integrating surveys of the frequency of homostyles in natural populations, DNA sequence analyses of the gene controlling the position of female sexual organs (CYPᵀ), and microsatellite genotyping of both progeny arrays and natural populations characterized by varying frequencies of homostyles. As expected, we found that homostyles displace short-styled individuals, but long-style morphs are maintained at low frequencies within populations. We also demonstrated that homostyles repeatedly evolved from short-styled individuals in association with different types of loss-of-function mutations in CYPᵀ. Additionally, homostyly triggers a shift to selfing, promoting increased inbreeding within and genetic differentiation among populations. Our results elucidate the causes and consequences of repeated transitions to homostyly within species, enabling a likely explanation for the fact that homostyly has not become fixed in P. vulgaris. This study represents a benchmark for future analyses of losses of heterostyly.

Reproductive Autonomy and Evolutionary Biology: A Regulatory Framework for Trait-Selection Technologies

1993 ◽  
Vol 19 (3) ◽  
pp. 187-231
Author(s):  
Owen D. Jones
Keyword(s):  
Reproductive Success ◽  
Supreme Court ◽  
Reproductive Strategies ◽  
Evolutionary Biology ◽  
Social Values ◽  
Inclusive Fitness ◽  
Regulatory System ◽  
Regulatory Framework ◽  
Reproductive Autonomy ◽  
Future Child

The Constitution protects, in some measure, each person's autonomy in making basic decisions about family, parenthood, and procreation. This Article examines the extent to which courts should protect from government intrusions a parent's access to technologies that influence specific characteristics of offspring. Beginning with Supreme Court opinions that articulate constitutional and social values regarding reproductive autonomy, the Article explores how important new insights from evolutionary biology may supplement an understanding of Human procreation. Specifically, the Article explains how trait selection can constitute an important part of larger “reproductive strategies” that powerfully affect an individual's “inclusive fitness” (itself a measure of reproductive success). It concludes that access to trait-selection technologies should receive the same federal protection from government intrusions as that afforded access to abortion. It proposes the first limit to that protection, however, when a parent seeks to select for a trait, or to use a technique, that would be clearly and significantly damaging to the future child. The Article subsequently divides the use of trait-selection technologies (TSTs) into eight contexts and proposes a preliminary framework by which a regulatory system could legitimately distinguish among them.

scholarly journals Fluctuating selection: the perpetual renewal of adaptation in variable environments

2010 ◽  
Vol 365 (1537) ◽  
pp. 87-97 ◽  
Author(s):  
Graham Bell
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Phenotypic Variance ◽  
Weak Selection ◽  
Fluctuating Selection ◽  
Environmental Variance ◽  
Strong Selection ◽  
Genomic Studies ◽  
Over Time

Darwin insisted that evolutionary change occurs very slowly over long periods of time, and this gradualist view was accepted by his supporters and incorporated into the infinitesimal model of quantitative genetics developed by R. A. Fisher and others. It dominated the first century of evolutionary biology, but has been challenged in more recent years both by field surveys demonstrating strong selection in natural populations and by quantitative trait loci and genomic studies, indicating that adaptation is often attributable to mutations in a few genes. The prevalence of strong selection seems inconsistent, however, with the high heritability often observed in natural populations, and with the claim that the amount of morphological change in contemporary and fossil lineages is independent of elapsed time. I argue that these discrepancies are resolved by realistic accounts of environmental and evolutionary changes. First, the physical and biotic environment varies on all time-scales, leading to an indefinite increase in environmental variance over time. Secondly, the intensity and direction of natural selection are also likely to fluctuate over time, leading to an indefinite increase in phenotypic variance in any given evolving lineage. Finally, detailed long-term studies of selection in natural populations demonstrate that selection often changes in direction. I conclude that the traditional gradualist scheme of weak selection acting on polygenic variation should be supplemented by the view that adaptation is often based on oligogenic variation exposed to commonplace, strong, fluctuating natural selection.

scholarly journals New therapeutic patents used for the treatment of leprosy: a review

2018 ◽  
Vol 146 (14) ◽  
pp. 1746-1749 ◽  
Author(s):  
Nayara Gomes Lima Santos ◽  
Karen Perez Pereira Ramos ◽  
Saravanan Shanmugam ◽  
Fernanda Oliveira de Carvalho ◽  
Luciana Garcez Barreto Teixeira ◽  
...  
Keyword(s):  
Peripheral Nerves ◽  
Peripheral Neuropathies ◽  
Loss Of Function ◽  
Cutaneous Lesions ◽  
Patent Classification ◽  
Human Needs ◽  
International Patent ◽  
Different Types ◽  
New Treatment

AbstractLeprosy is a granulomatous disease, infectious and transmissible, which affects the skin and peripheral nerves, havingMycobacterium lepraeas causative agent. The manifestation of this disease causes cutaneous lesions, peripheral neuropathies and, in more extreme cases, may generate deformities and disabilities in affected individuals. Patents were identified using the descriptor ‘leprosy’ and code A61K of the international patent classification, which indicates only products that meet human needs. The analysis was made using theWIPO,ESPACENETandUSPTOdatabases, until the month of September 2016. Through this review, we found a variety of in vitro, pre-clinical and clinical studies relating to the treatment of leprosy with different types of compounds and forms of administration. New treatment proposals should include pain reduction capabilities, prevention or limitation of the appearance of cutaneous lesions, as well as prevention of the progression of the disease to more severe stages that may lead to loss of function or potentiate the individual's immune response to theM. lepraebacillus in order to prevent bacterial spread. We concluded that any patents developed with natural products were not found in the treatment of leprosy. All the deposited products were synthetic origin, mostly tested in humans and of varied forms of administration.

Mutations in mouse Aristaless-like4 cause Strong's luxoid polydactyly

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2711-2721 ◽  
Author(s):  
S. Qu ◽  
S.C. Tucker ◽  
J.S. Ehrlich ◽  
J.M. Levorse ◽  
L.A. Flaherty ◽  
...  
Keyword(s):  
Limb Development ◽  
Evolutionary Biology ◽  
Biochemical Characterization ◽  
Limb Bud ◽  
Critical Threshold ◽  
Homeodomain Protein ◽  
Loss Of Function ◽  
Posterior Aspect ◽  
Vertebrate Limb Development ◽  
Zone Of Polarizing Activity

Mutations that affect vertebrate limb development provide insight into pattern formation, evolutionary biology and human birth defects. Patterning of the limb axes depends on several interacting signaling centers; one of these, the zone of polarizing activity (ZPA), comprises a group of mesenchymal cells along the posterior aspect of the limb bud that express sonic hedgehog (Shh) and plays a key role in patterning the anterior-posterior (AP) axis. The mechanisms by which the ZPA and Shh expression are confined to the posterior aspect of the limb bud mesenchyme are not well understood. The polydactylous mouse mutant Strong's luxoid (lst) exhibits an ectopic anterior ZPA and expression of Shh that results in the formation of extra anterior digits. Here we describe a new chlorambucil-induced deletion allele, lstAlb, that uncovers the lst locus. Integration of the lst genetic and physical maps suggested the mouse Aristaless-like4 (Alx4) gene, which encodes a paired-type homeodomain protein that plays a role in limb patterning, as a strong molecular candidate for the Strong's luxoid gene. In genetic crosses, the three lst mutant alleles fail to complement an Alx4 gene-targeted allele. Molecular and biochemical characterization of the three lst alleles reveal mutations of the Alx4 gene that result in loss of function. Alx4 haploinsufficiency and the importance of strain-specific modifiers leading to polydactyly are indicative of a critical threshold requirement for Alx4 in a genetic program operating to restrict polarizing activity and Shh expression in the anterior mesenchyme of the limb bud, and suggest that mutations in Alx4 may also underlie human polydactyly.

scholarly journals PRDM9 Diversity at Fine Geographical Scale Reveals Contrasting Evolutionary Patterns and Functional Constraints in Natural Populations of House Mice

2019 ◽  
Vol 36 (8) ◽  
pp. 1686-1700 ◽  
Author(s):  
Covadonga Vara ◽  
Laia Capilla ◽  
Luca Ferretti ◽  
Alice Ledda ◽  
Rosa A Sánchez-Guillén ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Rapid Evolution ◽  
Natural Populations ◽  
Global Scale ◽  
House Mice ◽  
Functional Constraints ◽  
Evolutionary Patterns ◽  
Data Set

Abstract One of the major challenges in evolutionary biology is the identification of the genetic basis of postzygotic reproductive isolation. Given its pivotal role in this process, here we explore the drivers that may account for the evolutionary dynamics of the PRDM9 gene between continental and island systems of chromosomal variation in house mice. Using a data set of nearly 400 wild-caught mice of Robertsonian systems, we identify the extent of PRDM9 diversity in natural house mouse populations, determine the phylogeography of PRDM9 at a local and global scale based on a new measure of pairwise genetic divergence, and analyze selective constraints. We find 57 newly described PRDM9 variants, this diversity being especially high on Madeira Island, a result that is contrary to the expectations of reduced variation for island populations. Our analysis suggest that the PRDM9 allelic variability observed in Madeira mice might be influenced by the presence of distinct chromosomal fusions resulting from a complex pattern of introgression or multiple colonization events onto the island. Importantly, we detect a significant reduction in the proportion of PRDM9 heterozygotes in Robertsonian mice, which showed a high degree of similarity in the amino acids responsible for protein–DNA binding. Our results suggest that despite the rapid evolution of PRDM9 and the variability detected in natural populations, functional constraints could facilitate the accumulation of allelic combinations that maintain recombination hotspot symmetry. We anticipate that our study will provide the basis for examining the role of different PRDM9 genetic backgrounds in reproductive isolation in natural populations.

scholarly journals Sewall Wright, 21 December 1889 - 3 March 1988

1990 ◽  
Vol 36 ◽  
pp. 567-579 ◽  
Keyword(s):  
Population Genetics ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Coat Colour ◽  
Balance Theory ◽  
Theory Of Evolution ◽  
Shifting Balance Theory ◽  
Sewall Wright ◽  
Shifting Balance ◽  
Active Research

Sewall Wright's active life spanned the development of genetics from a new discipline when the principles of inheritance were still being elucidated to the technology of recombinant gene construction and insertion. He was one of the major pioneers of population genetics, which gave a quantitative basis to the studies of evolution, of variation in natural populations and of animal and plant breeding. He contributed most significantly to methods and ideas over a long period, indeed his four volume treatise was written long after he formally ‘retired’ and his last paper (211) was published a few days before his death at the age of 98. In the field of population genetics Wright developed the method of path coefficients, which he used to analyse quantitative genetic variation and relationship, but which has been applied to subjects as diverse as economics, the ideas of inbreeding coefficient and F -statistics which form the basis of analysis of population structure, the theory of variation in gene frequency among populations, and the shifting balance theory of evolution, which remains a topic of active research and controversy. Wright contributed to physiological genetics, notably analysis of the inheritance of coat colour in the guinea pig, and in particular the epistatic relationships among the genes involved. There was a critical interplay between his population and physiological work, in that the analysis of finite populations on the one hand and of epistatic interactions on the other are the bases of Wright’s development of the shifting balance theory. A full and enlightening biography of Sewall Wright which traces his influence on evolutionary biology and his interactions with other important workers was published recently (Provine 1986) and shorter appreciations have appeared since his death, notably by Crow (1988), Wright’s long-time colleague. This biography relies heavily on Provine’s volume, and does no more than summarize Wright’s extensive contributions. Many of his important papers have been reprinted recently (1986).

scholarly journals Saccharomyces cerevisiae kinesin- and dynein-related proteins required for anaphase chromosome segregation.

1995 ◽  
Vol 128 (4) ◽  
pp. 617-624 ◽  
Author(s):  
W S Saunders ◽  
D Koshland ◽  
D Eshel ◽  
I R Gibbons ◽  
M A Hoyt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Motor Proteins ◽  
Cytoplasmic Dynein ◽  
Gene Products ◽  
Loss Of Function ◽  
Direct Role ◽  
Double Deletion ◽  
Different Types ◽  
Related Proteins

The Saccharomyces cerevisiae kinesin-related gene products Cin8p and Kip1p function to assemble the bipolar mitotic spindle. The cytoplasmic dynein heavy chain homologue Dyn1p (also known as Dhc1p) participates in proper cellular positioning of the spindle. In this study, the roles of these motor proteins in anaphase chromosome segregation were examined. While no single motor was essential, loss of function of all three completely halted anaphase chromatin separation. As combined motor activity was diminished by mutation, both the velocity and extent of chromatin movement were reduced, suggesting a direct role for all three motors in generating a chromosome-separating force. Redundancy for function between different types of microtubule-based motor proteins was also indicated by the observation that cin8 dyn1 double-deletion mutants are inviable. Our findings indicate that the bulk of anaphase chromosome segregation in S. cerevisiae is accomplished by the combined actions of these three motors.

scholarly journals Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures

2017 ◽  
Vol 114 (31) ◽  
pp. 8325-8329 ◽  
Author(s):  
Mathieu Chouteau ◽  
Violaine Llaurens ◽  
Florence Piron-Prunier ◽  
Mathieu Joron
Keyword(s):  
Evolutionary Biology ◽  
Natural Populations ◽  
Mate Preferences ◽  
Visual Signals ◽  
Wing Pattern ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Conservation Medicine ◽  
Local Diversity ◽  
Adaptive Diversity

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata. Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata. The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism.

scholarly journals A Mathematical Modeling Approach to the Cort-Fitness Hypothesis

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
F El Moustaid ◽  
S J Lane ◽  
I T Moore ◽  
L R Johnson
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Reproductive Strategies ◽  
Evolutionary Biology ◽  
Positive Relationship ◽  
Negative Relationship ◽  
Environmental Challenges ◽  
Field Endocrinology ◽  
Empirical Tests ◽  
The Relationship

Abstract The Cort-Fitness Hypothesis has generated much interest from investigators integrating field endocrinology with evolutionary biology, ecology, and conservation. The hypothesis was developed to test the assumption that if glucocorticoid levels increase with environmental challenges and fitness decreases with environmental challenges, then there should be a negative relationship between baseline glucocorticoid levels and fitness. Indeed, studies across diverse taxa have found that the relationship between baseline glucocorticoid levels and fitness are not consistent: some studies show a positive relationship, others negative, and some show no correlation. Hence, a deeper understanding of the mechanisms underlying the relationship between baseline glucocorticoid levels, environmental challenges, and fitness is needed. We propose a mathematical model representing the links between baseline glucocorticoid levels, environmental challenges, and fitness. Our model describes how variation in the predictability and intensity of environmental challenges, reproductive strategies, and fitness metrics can all contribute to the variability observed in empirical tests of the Cort-Fitness Hypothesis. We provide qualitative results showing that much of the inconsistency in previous studies can be explained and we discuss how the model can be used to inform future Cort-Fitness studies.

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