Rossiter Henry Crozier 1943 - 2009

2011 ◽  
Vol 22 (1) ◽  
pp. 80 ◽  
Author(s):  
Benjamin P. Oldroyd ◽  
Oliver Mayo
Keyword(s):  
Kin Selection ◽  
Heart Attack ◽  
Social Insect ◽  
Molecular Genetic ◽  
Evolutionary Genetics ◽  
Explanatory Theory ◽  
Mutation Pressure ◽  
James Cook ◽  
Directional Mutation Pressure ◽  
Insect Populations

Ross Crozier, population geneticist and leader in the study of the evolutionary genetics of social insects, was born on 4 January 1943 in Jodhpur, India. He died of a heart attack in his office at James Cook University in Townsville on 12 November 2009. He is survived by his wife Yuen Ching Kok, who was his inseparable companion and collaborator in life as in the laboratory. Crozier was a pioneer in the application of molecular genetic markers to the analysis of social insect populations, and generated much of the theory that made these analyses possible. Ross and Ching Crozier produced the first sequence of the honey bee mitochondrial genome?the second insect mitochondria to be fully sequenced. From the sequence Crozier produced fundamental insights into the nature of DNA evolution, particularly directional mutation pressure towards particular nucleotides. Crozier contributed massively to the development of kin selection theory, which remains the most potent explanatory theory for the evolution of social behaviour in insects.

Unbiased Estimation of Symmetrical Directional Mutation Pressure from Protein-Coding DNA

1996 ◽  
Vol 42 (4) ◽  
pp. 476-480 ◽  
Author(s):  
Lars S. Jermiin ◽  
Peter G. Foster ◽  
Dan Graur ◽  
Roger M. Lowe ◽  
Ross H. Crozier
Keyword(s):  
Unbiased Estimation ◽  
Mutation Pressure ◽  
Protein Coding ◽  
Directional Mutation Pressure

Unbiased estimation of symmetrical directional mutation pressure from protein-coding DNA

1996 ◽  
Vol 42 (4) ◽  
pp. 476-480 ◽  
Author(s):  
Lars S. Jermiin ◽  
Peter G. Foster ◽  
Dan Graur ◽  
Roger M. Lowe ◽  
Ross H. Crozier
Keyword(s):  
Unbiased Estimation ◽  
Mutation Pressure ◽  
Protein Coding ◽  
Directional Mutation Pressure

Insect mitochondrial genomics 2: the complete mitochondrial genome sequence of a giant stonefly, Pteronarcys princeps, asymmetric directional mutation bias, and conserved plecopteran A+T-region elements

Genome ◽  
2006 ◽  
Vol 49 (7) ◽  
pp. 815-824 ◽  
Author(s):  
James Bruce Stewart ◽  
Andrew T Beckenbach
Keyword(s):  
Genome Sequence ◽  
Genome Rearrangement ◽  
Complete Mitochondrial Genome ◽  
Nucleotide Composition ◽  
Genome Sequences ◽  
Mutation Pressure ◽  
Stem Loop ◽  
Mitochondrial Genomics ◽  
Directional Mutation Pressure ◽  
Mt Genome

Mitochondrial (mt) genome sequences of insects are receiving renewed attention in molecular phylogentic studies, studies of mt-genome rearrangement, and other unusual molecular phenomena, such as translational frameshifting. At present, the basal neopteran lineages are poorly represented by mt-genome sequences. Complete mt-genome sequences are available in the databases for only the Orthoptera and Blatteria; 9 orders are unrepresented. Here, we present the complete mt-genome sequence of a giant stonefly, Pteronarcys princeps (Plecoptera; Pteronarcyidae). The 16 004 bp genome is typical in its genome content, gene organisation, and nucleotide composition. The genome shows evidence of strand-specific mutational biases, correlated with the time between the initiation of leading and the initiation of lagging strand replication. Comparisons with other insects reveal that this trend is seen in other insect groups, but is not universally consistent among sampled mt-genomes. The A+T region is compared with that of 2 stoneflies in the family Peltoperlidae. Conserved stem-loop structures and sequence blocks are noted between these distantly related families.Key words: mitochondrial genomics, directional mutation pressure, A+T-rich region, Plecoptera, stonefly.

scholarly journals The sensitivity of a honeybee colony to worker mortality depends on season and resource availability

2020 ◽  
Author(s):  
Natalie J Lemanski ◽  
Siddhant Bansal ◽  
Nina H Fefferman
Keyword(s):  
Environmental Change ◽  
Resource Availability ◽  
Honey Bees ◽  
Social Insect ◽  
Seasonal Differences ◽  
Extrinsic Mortality ◽  
Age Dependent ◽  
Honeybee Colony ◽  
Insect Populations ◽  
Age Independent

Abstract Background: Honeybees have extraordinary phenotypic plasticity in their senescence rate, making them a fascinating model system for the evolution of aging. Seasonal variation in senescence and extrinsic mortality results in a tenfold increase in worker life expectancy in winter as compared to summer. To understand the evolution of this remarkable pattern of aging, we must understand how individual longevity scales up to effects on the entire colony. In addition, threats to the health of honey bees and other social insects are typically measured at the individual level. To predict the effects of environmental change on social insect populations, we must understand how individual effects impact colony performance. We develop a matrix model of colony demographics to ask how worker age-dependent and age-independent mortality affect colony fitness and how these effects differ by seasonal conditions. Results: We find that there are seasonal differences in honeybee colony elasticity to both senescent and extrinsic worker mortality. Colonies are most elastic to extrinsic (age-independent) nurse and forager mortality during periods of higher extrinsic mortality and resource availability but most elastic to age-dependent mortality during periods of lower extrinsic mortality and lower resource availability.Conclusions: These results suggest that seasonal changes in the strength of selection on worker senescence partly explain the observed pattern of seasonal differences in worker aging in honey bees. More broadly, these results extend our understanding of the role of extrinsic mortality in the evolution of senescence to social animals and improve our ability to model the effects of environmental change on social insect populations of economic or conservation concern.

scholarly journals Reproductive parasitism in insects. The interaction of host and bacteria

2021 ◽  
Vol 66 (1) ◽  
Author(s):  
Irina Goryacheva ◽  
Boris Andrianov
Keyword(s):  
Genetic Factors ◽  
Cytoplasmic Incompatibility ◽  
Molecular Genetic ◽  
Practical Importance ◽  
Symbiotic System ◽  
Non Invasive ◽  
Reproductive Parasitism ◽  
Sex Development ◽  
Genetic Mechanisms ◽  
Insect Populations

Reproductive parasitism is a specific form of symbiosis in which a microorganism alters the reproduction of the host by interfering with the mechanisms of sex development. The review considers four changes in reproduction — male killing, parthenogenesis, feminization, and cytoplasmic incompatibility — determined by cytoplasmic bacteria. The cytogenetic and molecular genetic mechanisms of interaction between partners in the symbiotic system are discussed, including the comparative analysis of molecular-genetic factors responsible for reproductive parasitism. The features of the interaction between an insect and bacteria in symbiosis with various systems for determining the sex of the host, male and female heterogamy and haplodiploidy, are considered. Studies of cytoplasmic incompatibility are of great practical importance, since they open up prospects for non-invasive engineering on natural insect populations for biocontrol.

scholarly journals Genomics of clinal local adaptation in Pinus sylvestris under continuous environmental and spatial genetic setting

2019 ◽  
Author(s):  
Jaakko S. Tyrmi ◽  
Jaana Vuosku ◽  
Juan J. Acosta ◽  
Zhen Li ◽  
Lieven Sterck ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Local Adaptation ◽  
Large Scale ◽  
Molecular Genetic ◽  
Natural Populations ◽  
Keystone Species ◽  
Evolutionary Genetics ◽  
Genomic Diversity ◽  
Landscape Genomics ◽  
Polygenic Adaptation

AbstractUnderstanding the consequences of local adaptation at the genomic diversity is a central goal in evolutionary genetics of natural populations. In species with large continuous geographical distributions the phenotypic signal of local adaptation is frequently clear, but the genetic background often remains elusive. We examined the patterns of genetic diversity in Pinus sylvestris, a keystone species in many Eurasian ecosystems with a huge distribution range and decades of forestry research showing that it is locally adapted to the vast range of environmental conditions. Making P. sylvestris an even more attractive subject of local adaptation study, population structure has been shown to be weak previously and in this study. However, little is known about the molecular genetic basis of adaptation, as the massive size of gymnosperm genomes has prevented large scale genomic surveys. We generated a both geographically and genomically extensive dataset using a targeted sequencing approach. By applying divergence-based and landscape genomics methods we found that several coding loci contribute to local adaptation. We also discovered a very large (ca. 300 Mbp) putative inversion with a signal of local adaptation, which to our knowledge is the first such discovery in conifers. Our results call for more detailed analysis of structural variation in relation to genomic basis of local adaptation, emphasize the lack of large effect loci contributing to local adaptation in the coding regions and thus point out to the need for more attention towards multi-locus analysis of polygenic adaptation.

Sign in / Sign up

Export Citation Format

Share Document