scholarly journals Low levels of sequence divergence in rock wallabies (Petrogale) suggest a lack of positive directional selection in SRY

1997 ◽  
Vol 14 (3) ◽  
pp. 350-353 ◽  
Author(s):  
R. J. O'Neill ◽  
M. D. Eldridge ◽  
R. H. Crozier ◽  
J. A. Graves
Keyword(s):  
Sequence Divergence ◽  
Directional Selection ◽  
Low Levels

scholarly journals Hybrid Incompatibilities and Transgressive Gene Expression Between Two Closely Related Subspecies of Drosophila

2020 ◽  
Vol 11 ◽  
Author(s):  
Alwyn C. Go ◽  
Alberto Civetta
Keyword(s):  
Gene Networks ◽  
Sequence Divergence ◽  
Regulatory Elements ◽  
Directional Selection ◽  
Stabilizing Selection ◽  
Sequence Evolution ◽  
Snp Data ◽  
Partial Isolation ◽  
Cascade Effects ◽  
Hybrid Dysfunction

Genome-wide assays of expression between species and their hybrids have identified genes that become either over- or underexpressed relative to the parental species (i.e., transgressive). Transgressive expression in hybrids is of interest because it highlights possible changes in gene regulation linked to hybrid dysfunction. Previous studies in Drosophila that used long-diverged species pairs with complete or nearly complete isolation (i.e., full sterility and partial inviability of hybrids) and high-levels of genome misregulation have found correlations between expression and coding sequence divergence. The work highlighted the possible effects of directional selection driving sequence divergence and transgressive expression. Whether the same is true for taxa at early stages of divergence that have only achieved partial isolation remains untested. Here, we reanalyze previously published genome expression data and available genome sequence reads from a pair of partially isolated subspecies of Drosophila to compare expression and sequence divergence. We find a significant correlation in rates of expression and sequence evolution, but no support for directional selection driving transgressive expression in hybrids. We find that most transgressive genes in hybrids show no differential expression between parental subspecies and used SNP data to explore the role of stabilizing selection through compensatory mutations. We also examine possible misregulation through cascade effects that could be driven by interacting gene networks or co-option of off-target cis-regulatory elements.

scholarly journals β-fibrinogen intron 7 variation in Discoglossus (Anura: Discoglossidae): implications for the taxonomic assessment of morphologically cryptic species

2008 ◽  
Vol 29 (4) ◽  
pp. 523-533 ◽  
Author(s):  
Mario García-París ◽  
Iñigo Martínez-Solano ◽  
Guillermo Velo-Antón
Keyword(s):  
Iberian Peninsula ◽  
Incomplete Lineage Sorting ◽  
Sequence Divergence ◽  
Taxonomic Status ◽  
Lineage Sorting ◽  
Base Pairs ◽  
Molecular Systematic ◽  
Nuclear Introns ◽  
Geographic Patterns ◽  
Low Levels

AbstractThe generalized use of nuclear introns in combination with mitochondrial DNA data in molecular systematic and intraspecific phylogeographical studies is providing new insights into the complex evolutionary histories of taxa surviving the Quaternary glaciations. Previous studies have highlighted the suitability of the beta-fibrinogen intron 7 (β-fibint7) for phylogenetic and phylogeographic studies in a wide variety of taxa, including amphibians. Here we use sequences of this marker to assess inter- and intraspecific variation in Discoglossus (Discoglossidae), with special emphasis on geographic patterns of genetic structure in the Iberian Peninsula, where recent studies have questioned the taxonomic status of D. jeanneae. We obtained 81 sequences of β-fibint7 from samples including all currently recognized species except D. montalentii and 37 populations in the Iberian Peninsula and compared levels of genetic variation with those observed in a fragment of similar length of the mtDNA gene cytochrome b. The sequence of β-fibint7 in Discoglossus is the shortest described for amphibians so far, 378 base pairs. In general, we found low levels of variability (only 26 parsimony-informative sites in the dataset), with no alternatively fixed haplotypes in samples attributed to D. galganoi or D. jeanneae based on their mtDNA. Values of pairwise sequence divergence between non-Iberian species ranged from 1.1% to 4.5% (13.3% to 20.9% in mtDNA). The patterns observed in samples from the Iberian Peninsula are consistent with either incomplete lineage sorting or ongoing gene flow between D. galganoi and D. jeanneae. We conclude by reviewing the genetic evidence available to address the taxonomic status of Iberian species of Discoglossus.

Evolution of host range in the follicle mite Demodex kutzeri

Parasitology ◽  
2016 ◽  
Vol 144 (5) ◽  
pp. 594-600 ◽  
Author(s):  
MICHAEL F. PALOPOLI ◽  
VAN TRA ◽  
KASSEY MATOIN ◽  
PHUONG D. MAC
Keyword(s):  
Host Species ◽  
Common Ancestor ◽  
Mule Deer ◽  
Divergence Time ◽  
Sequence Divergence ◽  
Mitochondrial Genes ◽  
Species Boundaries ◽  
Previous Estimate ◽  
The Family ◽  
Low Levels

SUMMARYThe sequences of four mitochondrial genes were determined for Demodex mites isolated from two distantly related species within the family Cervidae, and identified morphologically as belonging to the species Demodex kutzeri. The sequences were used to test the hypothesis that Demodex are strictly host-specific, and hence cospeciate with their hosts: (1) The estimated divergence time between mites found on elk vs humans agreed closely with a previous estimate of the time that these host species last shared a common ancestor, suggesting cospeciation of mites and hosts, at least over long evolutionary timescales. (2) The extremely low levels of sequence divergence between the mites found on elk vs mule deer hosts indicated that these mites belong to the same species, which suggests that Demodex are able to move across host species boundaries over shorter timescales. Together, the results are consistent with the model that Demodex mites are not strict host-specialists, but instead lose the ability to move between host lineages gradually.

Many Migraineurs Have Low Levels of Vitamin D

2008 ◽  
Vol 41 (18) ◽  
pp. 16
Author(s):  
DIANA MAHONEY
Keyword(s):  
Vitamin D ◽  
Low Levels

Social Motives Predict Loneliness During a Developmental Transition

2017 ◽  
Vol 76 (4) ◽  
pp. 145-153 ◽  
Author(s):  
Jana Nikitin ◽  
Alexandra M. Freund
Keyword(s):  
Social Relationships ◽  
Well Being ◽  
Social Avoidance ◽  
Social Approach ◽  
Social Motives ◽  
Developmental Transitions ◽  
Avoidance Motivation ◽  
Negative Effect ◽  
Low Levels

Abstract. Establishing new social relationships is important for mastering developmental transitions in young adulthood. In a 2-year longitudinal study with four measurement occasions (T1: n = 245, T2: n = 96, T3: n = 103, T4: n = 85), we investigated the role of social motives in college students’ mastery of the transition of moving out of the parental home, using loneliness as an indicator of poor adjustment to the transition. Students with strong social approach motivation reported stable and low levels of loneliness. In contrast, students with strong social avoidance motivation reported high levels of loneliness. However, this effect dissipated relatively quickly as most of the young adults adapted to the transition over a period of several weeks. The present study also provides evidence for an interaction between social approach and social avoidance motives: Social approach motives buffered the negative effect on social well-being of social avoidance motives. These results illustrate the importance of social approach and social avoidance motives and their interplay during developmental transitions.

Quota Women Are Threatening to Men

2017 ◽  
Vol 76 (3) ◽  
pp. 107-116 ◽  
Author(s):  
Klea Faniko ◽  
Till Burckhardt ◽  
Oriane Sarrasin ◽  
Fabio Lorenzi-Cioldi ◽  
Siri Øyslebø Sørensen ◽  
...  
Keyword(s):  
Decision Making ◽  
Organizational Performance ◽  
Gender Stereotypes ◽  
Perceived Threat ◽  
Preferential Treatment ◽  
Public Sector Employees ◽  
Different Types ◽  
Low Levels ◽  
Women In Decision Making ◽  
The Impact

Abstract. Two studies carried out among Albanian public-sector employees examined the impact of different types of affirmative action policies (AAPs) on (counter)stereotypical perceptions of women in decision-making positions. Study 1 (N = 178) revealed that participants – especially women – perceived women in decision-making positions as more masculine (i.e., agentic) than feminine (i.e., communal). Study 2 (N = 239) showed that different types of AA had different effects on the attribution of gender stereotypes to AAP beneficiaries: Women benefiting from a quota policy were perceived as being more communal than agentic, while those benefiting from weak preferential treatment were perceived as being more agentic than communal. Furthermore, we examined how the belief that AAPs threaten men’s access to decision-making positions influenced the attribution of these traits to AAP beneficiaries. The results showed that men who reported high levels of perceived threat, as compared to men who reported low levels of perceived threat, attributed more communal than agentic traits to the beneficiaries of quotas. These findings suggest that AAPs may have created a backlash against its beneficiaries by emphasizing gender-stereotypical or counterstereotypical traits. Thus, the framing of AAPs, for instance, as a matter of enhancing organizational performance, in the process of policy making and implementation, may be a crucial tool to countering potential backlash.

Domestic Integration and Suicide in the Provinces of Canada

Crisis ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 59-63 ◽  
Author(s):  
Antoon A. Leenaars ◽  
David Lester
Keyword(s):  
Social Factors ◽  
Positive Association ◽  
Negative Association ◽  
Birth Rates ◽  
Marriage Rates ◽  
Suicide Rates ◽  
The Social ◽  
Divorce Rates ◽  
Low Levels ◽  
Over Time

Canada's rate of suicide varies from province to province. The classical theory of suicide, which attempts to explain the social suicide rate, stems from Durkheim, who argued that low levels of social integration and regulation are associated with high rates of suicide. The present study explored whether social factors (divorce, marriage, and birth rates) do in fact predict suicide rates over time for each province (period studied: 1950-1990). The results showed a positive association between divorce rates and suicide rates, and a negative association between birth rates and suicide rates. Marriage rates showed no consistent association, an anomaly as compared to research from other nations.

Measures of RSA Suppression, Attentional Control, and Negative Affect Predict Self-Ratings of Executive Functions

2011 ◽  
Vol 25 (4) ◽  
pp. 164-173 ◽  
Author(s):  
Brian Healy ◽  
Aaron Treadwell ◽  
Mandy Reagan
Keyword(s):  
College Students ◽  
Heart Rate ◽  
Regression Analysis ◽  
Individual Differences ◽  
Negative Affect ◽  
Respiratory Sinus Arrhythmia ◽  
Attentional Control ◽  
Executive Processes ◽  
Sinus Arrhythmia ◽  
Low Levels

The current study was an attempt to determine the degree to which the suppression of respiratory sinus arrhythmia (RSA) and attentional control were influential in the ability to engage various executive processes under high and low levels of negative affect. Ninety-four college students completed the Stroop Test while heart rate was being recorded. Estimates of the suppression of RSA were calculated from each participant in response to this test. The participants then completed self-ratings of attentional control, negative affect, and executive functioning. Regression analysis indicated that individual differences in estimates of the suppression of RSA, and ratings of attentional control were associated with the ability to employ executive processes but only when self-ratings of negative affect were low. An increase in negative affect compromised the ability to employ these strategies in the majority of participants. The data also suggest that high attentional control in conjunction with attenuated estimates of RSA suppression may increase the ability to use executive processes as negative affect increases.

Sign in / Sign up

Export Citation Format

Share Document