scholarly journals Variance in developmental event timing is greatest at low biological levels: implications for heterochrony

2013 ◽  
Vol 110 (3) ◽  
pp. 581-590 ◽  
Author(s):  
Oliver Tills ◽  
Simon D. Rundle ◽  
John I. Spicer
Keyword(s):  
Developmental Event ◽  
Event Timing

scholarly journals Parent–offspring similarity in the timing of developmental events: an origin of heterochrony?

2013 ◽  
Vol 280 (1769) ◽  
pp. 20131479 ◽  
Author(s):  
Oliver Tills ◽  
Simon D. Rundle ◽  
John I. Spicer
Keyword(s):  
High Resolution ◽  
Embryonic Development ◽  
Intraspecific Variation ◽  
Genetic Basis ◽  
Raw Material ◽  
Pond Snail ◽  
Developmental Event ◽  
Event Timing ◽  
Radix Balthica ◽  
Temporal And Spatial

Understanding the link between ontogeny (development) and phylogeny (evolution) remains a key aim of biology. Heterochrony, the altered timing of developmental events between ancestors and descendants, could be such a link although the processes responsible for producing heterochrony, widely viewed as an interspecific phenomenon, are still unclear. However, intraspecific variation in developmental event timing, if heritable, could provide the raw material from which heterochronies originate. To date, however, heritable developmental event timing has not been demonstrated, although recent work did suggest a genetic basis for intraspecific differences in event timing in the embryonic development of the pond snail, Radix balthica . Consequently, here we used high-resolution (temporal and spatial) imaging of the entire embryonic development of R. balthica to perform a parent–offspring comparison of the timing of twelve, physiological and morphological developmental events. Between-parent differences in the timing of all events were good predictors of such timing differences between their offspring, and heritability was demonstrated for two of these events (foot attachment and crawling). Such heritable intraspecific variation in developmental event timing could be the raw material for speciation events, providing a fundamental link between ontogeny and phylogeny, via heterochrony.

The Effect of Event Timing Characteristics on Causal Contingency Learning

2004 ◽  
Author(s):  
Marci Sammons ◽  
Sharon Mutter ◽  
Leslie Plumlee ◽  
Laura Strain
Keyword(s):  
Contingency Learning ◽  
Event Timing

APPLICATION OF PORTABLE XRF TO STRATIGRAPHIC STUDIES AND EVENT TIMING IN IOWA GLACIAL DEPOSITS

2019 ◽  
Author(s):  
Stephanie Tassier-Surine ◽  
◽  
Phillip J. Kerr ◽  
Kathleen R. Goff ◽  
Nick Lefler
Keyword(s):  
Portable Xrf ◽  
Glacial Deposits ◽  
Event Timing

scholarly journals Change in heart period: A function of sensorimotor event timing within the cardiac cycle

1977 ◽  
Vol 5 (3) ◽  
pp. 383-393 ◽  
Author(s):  
Beatrice C. Lacey ◽  
John I. Lacey
Keyword(s):  
Cardiac Cycle ◽  
Heart Period ◽  
Event Timing

scholarly journals Forces drive basement membrane invasion inCaenorhabditis elegans

2018 ◽  
Vol 115 (45) ◽  
pp. 11537-11542 ◽  
Author(s):  
Rodrigo Cáceres ◽  
Nagagireesh Bojanala ◽  
Laura C. Kelley ◽  
Jes Dreier ◽  
John Manzi ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Basement Membrane ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Force Production ◽  
Developmental Event ◽  
C Elegans ◽  
Anchor Cell

During invasion, cells breach basement membrane (BM) barriers with actin-rich protrusions. It remains unclear, however, whether actin polymerization applies pushing forces to help break through BM, or whether actin filaments play a passive role as scaffolding for targeting invasive machinery. Here, using the developmental event of anchor cell (AC) invasion inCaenorhabditis elegans, we observe that the AC deforms the BM and underlying tissue just before invasion, exerting forces in the tens of nanonewtons range. Deformation is driven by actin polymerization nucleated by the Arp2/3 complex and its activators, whereas formins and cross-linkers are dispensable. Delays in invasion upon actin regulator loss are not caused by defects in AC polarity, trafficking, or secretion, as appropriate markers are correctly localized in the AC even when actin is reduced and invasion is disrupted. Overall force production emerges from this study as one of the main tools that invading cells use to promote BM disruption inC. elegans.

scholarly journals The Development of Infants’ Expectations for Event Timing

2019 ◽  
Vol 7 (3) ◽  
pp. 219-242 ◽  
Author(s):  
Kyle J. Comishen ◽  
Scott A. Adler
Keyword(s):  
Target Location ◽  
Temporal Information ◽  
Brain Maturation ◽  
Limiting Factor ◽  
Anticipatory Eye Movements ◽  
Event Timing ◽  
Temporal Cues ◽  
Temporal Events ◽  
The Right ◽  
Visual Expectation

The capacity to process and incorporate temporal information into behavioural decisions is an integral component for functioning in our environment. Whereas previous research has extended adults’ temporal processing capacity down the developmental timeline to infants, little research has examined infants’ capacity to use that temporal information in guiding their future behaviours and whether this capacity can detect event-timing differences on the order of milliseconds. The present study examined 3- and 6-month-old infants’ ability to process temporal durations of 700 and 1200 milliseconds by means of the Visual Expectation Cueing Paradigm in which the duration of a central stimulus predicted either a target appearing on the left or on the right of a screen. If 3- and 6-month-old infants could discriminate the milliseconds difference between the centrally-presented temporal cues, then they would correctly make anticipatory eye movements to the proper target location at a rate above chance. Results indicated that 6- but not 3-month-olds successfully discriminated and incorporated events’ temporal information into their visual expectations. Brain maturation and the perceptual capacity to discriminate the relative timing values of temporal events may account for these findings. This developmental limitation in processing and discriminating events on the scale of milliseconds, consequently, may be a limiting factor for attentional and cognitive development that has not previously been explored.

scholarly journals Analysis of stochastic timing of intracellular events with gene switching

2019 ◽  
Author(s):  
Khem Raj Ghusinga ◽  
Abhyudai Singh
Keyword(s):  
First Passage Time ◽  
Regulatory Protein ◽  
Gene Activation ◽  
Threshold Level ◽  
Passage Time ◽  
First Passage ◽  
Cellular Processes ◽  
Event Timing ◽  
Activation Rates ◽  
Gene Switching

AbstractAn important step in execution of several cellular processes is accumulation of a regulatory protein up to a specific threshold level. Since production of a protein is inherently stochastic, the time at which its level crosses a threshold exhibits cell-to-cell variation. A problem of interest is to characterize how the statistics of event timing is affected by various steps of protein expression. Our previous work studied this problem by considering a gene expression model where gene was always active. Here we extend our analysis to a scenario where gene stochastically switches between active and inactive states. We formulate event timing as the first-passage time for a protein’s level to cross a threshold and investigate how the rates of gene activation/inactivation affect the distribution and moments of the first-passage time. Our results show that both the time-scale of gene switching with respect to the protein degradation rate as well as the ratio of the gene inactivation to gene activation rates are important parameters in shaping the event-timing distribution.

Feedforward genetic circuits regulate the precision of event timing

2021 ◽  
Author(s):  
Supravat Dey ◽  
Sherin Kannoly ◽  
Pavol Bokes ◽  
John J Dennehy ◽  
Abhyudai Singh
Keyword(s):  
Genetic Circuits ◽  
Event Timing
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