Jonathan B. Losos

Bio: Jonathan B. Losos is an academic researcher from Washington University in St. Louis. The author has contributed to research in topics: Anolis & Adaptive radiation. The author has an hindex of 89, co-authored 274 publications receiving 28673 citations. Previous affiliations of Jonathan B. Losos include University of California, Davis & Avila University.

The erratic and contingent progression of research on territoriality: a case study

Abstract: Our understanding of animal mating systems has changed dramatically with the advent of molecular methods to determine individuals’ reproductive success. But why are older behavioral descriptions and newer genetic descriptions of mating systems often seemingly inconsistent? We argue that a potentially important reason for such inconsistencies is a research trajectory rooted in early studies that were equivocal and overreaching, followed by studies that accepted earlier conclusions at face value and assumed, rather than tested, key ideas about animal mating systems. We illustrate our argument using Anolis lizards, whose social behavior has been studied for nearly a century. A dominant view emerging from this behavioral research was that anoles display strict territorial polygyny, where females mate with just the one male in whose territory they reside. However, all genetic evidence suggests that females frequently mate with multiple males. We trace this mismatch to early studies that concluded that anoles are territorial based on limited data. Subsequent research assumed territoriality implicitly or explicitly, resulting in studies that were unlikely to uncover or consider important any evidence of anoles’ departures from strict territorial polygyny. Thus, descriptions of anole behavior were largely led away from predicting a pattern of female multiple mating. We end by considering the broader implications of such erratic trajectories for the study of animal mating systems and posit that precise definitions, renewed attention to natural history, and explicitly questioning assumptions made while collecting behavioral observations will allow us to move towards a fuller understanding of animal mating systems. Mismatches between behavioral and genetic descriptions of mating systems are widespread across animals. We argue that these discrepancies can arise from the erratic and contingent progression of research on space use behavior and social interactions. We demonstrate such a trajectory in Anolis lizards, where decades of behavioral data led not only to the conclusion that anoles are territorial but also to the erroneous expectation, disproven by genetic evidence, that each female mates with just one male. The earliest studies concluded that anoles are territorial based on flimsy evidence, leading subsequent studies to implicitly and explicitly assume territorial behavior; later studies were thus unlikely to detect, or consider important, departures from territoriality that could facilitate female multiple mating. Such research trajectories are likely not unique to anoles, and we contend that avoiding these trajectories requires renewed and continued attention to the natural history of even well-studied organisms.

Interspecific aggression between Anolis cristatellus and A. gundlachi : comparison of sympatric and allopatric populations

Abstract: proximately 140 days, as compared to the turtle T. scripta which has enough stored lipids to support a standard metabolic rate at 28 C (0.09 cm3 O2/g/h, N = 5; SE = 0.10; R. Fischer, unpubl. data) for approximately 55 days. The large amount of NPL transferred from egg to hatchling (PIC) in alligators has apparently been made to fuel the prolonged period when hatchlings have a negative energy balance. The level of allocation to PIC is far from trivial, and in those reptiles examined, exceeds 50% of the egg lipids (Kramer and Bennett, 1981; Congdon et al., 1983a, b; Troyer, 1983; Wilhoft, 1986; Congdon, 1989; Congdon and Gibbons, 1989). Thus, the findings in this study along with the work done by Troyer (1983) on green iguanas may indicate that levels of PIC are determined by increases in fitness obtained by the female parent through investment in egg material, in excess of that needed for embryogenesis, that enhance survival of the neonate during the post-hatching period when energy balance is negative.

Estimating encounter rates as the first step of sexual selection in the lizard Anolis sagrei .

Abstract: How individuals move through their environment dictates which other individuals they encounter, determining their social and reproductive interactions and the extent to which they experience sexual selection. Specifically, females rarely have the option of mating with all males in a population-they can only choose among the males they encounter. Further, quantifying phenotypic differences between the males that females encounter and those that sire females' offspring lends insight into how social and reproductive interactions shape male phenotypes. We used an explicitly spatio-temporal Markov chain model to estimate the number of potential mates of Anolis sagrei lizards from their movement behaviour, and used genetic paternity assignments to quantify sexual selection on males. Females frequently encountered and mated with multiple males, offering ample opportunity for female mate choice. Sexual selection favoured males that were bigger and moved over larger areas, though the effect of body size cannot be disentangled from last-male precedence. Our approach corroborates some patterns of sexual selection previously hypothesized in anoles based on describing them as territorial, whereas other results, including female multiple mating itself, are at odds with territorial polygyny, offering insight into discrepancies in other taxa between behavioural and genetic descriptions of mating systems.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Human biochemical genetics

Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

phytools: an R package for phylogenetic comparative biology (and other things)

Abstract: Summary 1. Here, I present a new, multifunctional phylogenetics package, phytools, for the R statistical computing environment. 2. The focus of the package is on methods for phylogenetic comparative biology; however, it also includes tools for tree inference, phylogeny input/output, plotting, manipulation and several other tasks. 3. I describe and tabulate the major methods implemented in phytools, and in addition provide some demonstration of its use in the form of two illustrative examples. 4. Finally, I conclude by briefly describing an active web-log that I use to document present and future developments for phytools. I also note other web resources for phylogenetics in the R computational environment.

Testing for phylogenetic signal in comparative data: behavioral traits are more labile.

Abstract: The primary rationale for the use of phylogenetically based statistical methods is that phylogenetic signal, the tendency for related species to resemble each other, is ubiquitous. Whether this assertion is true for a given trait in a given lineage is an empirical question, but general tools for detecting and quantifying phylogenetic signal are inadequately developed. We present new methods for continuous-valued characters that can be implemented with either phylogenetically independent contrasts or generalized least-squares models. First, a simple randomization procedure allows one to test the null hypothesis of no pattern of similarity among relatives. The test demonstrates correct Type I error rate at a nominal α = 0.05 and good power (0.8) for simulated datasets with 20 or more species. Second, we derive a descriptive statistic, K, which allows valid comparisons of the amount of phylogenetic signal across traits and trees. Third, we provide two biologically motivated branch-length transformat...