BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Europe/Vienna
BEGIN:DAYLIGHT
DTSTART:20260329T030000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
TZNAME:CEST
END:DAYLIGHT
BEGIN:STANDARD
DTSTART:20251026T020000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:CET
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20260415T110108Z
UID:1764936000@ist.ac.at
DTSTART:20251205T130000
DTEND:20251205T140000
DESCRIPTION:Speaker: Diego Garcia Castillo\nhosted by Calin Guet\nAbstract:
  Rapid local adaptation to new environments is critical for species persis
 tence\, especially in introduced populations. The evolutionary success of 
 these populations is fundamentally dictated by the organization of genetic
  variation—the genomic architecture—in the face of severe demographic 
 constraints\, such as the founder effects and genetic bottlenecks that fre
 quently accompany colonization. A central question in evolutionary biology
  is whether rapid adaptation relies on major-effect loci\, such as chromos
 omal inversions\, or on many small-effect loci dispersed across the genome
 . Furthermore\, the genomic architecture strongly influences the extent to
  which evolutionary outcomes are predictable. Using introduced populations
  of the marine snail\, Littorina saxatilis\, as a model\, this thesis inve
 stigates how genetic variation and genomic structure drive adaptation foll
 owing introduction. We employed a comparative genomics approach on experim
 entally and accidentally introduced populations to dissect the specific ge
 nomic features that underpin divergence in newly colonized environments.In
  Chapter 2\, we tested the predictability of local adaptation through an u
 ncommon 30-year transplant experiment in nature. By distinguishing allele 
 and chromosomal inversion frequency changes from neutral expectations\, we
  found that evolutionary change was highly predictable at the macro-scale 
 (phenotypes and chromosomal inversions)\, but less robust at the level of 
 individual collinear loci. This result demonstrates that evolution can be 
 predictable when a population possesses sufficient standing genetic variat
 ion (SGV)\, with chromosomal inversions acting as key integrated units tha
 t facilitate a rapid response to selection. Building on this\, Chapter 3 a
 pplied whole-genome sequencing to three accidentally introduced population
 s (Venice\, San Francisco\, and Redwood City) to investigate their likely 
 source and genomic patterns of divergence. We identified genomic regions o
 f remarkable divergence potentially associated with local adaptation\, and
  likely fuelled by SGV\, while explicitly acknowledging the difficulty in 
 disentangling these selection signals from the genome-wide effects of demo
 graphic processes. Furthermore\, we found that the divergence patterns rel
 ied extensively on the collinear genome in these introduced populations\, 
 and less clearly on the chromosomal inversions. This observation contrasts
  with local adaptation observed in the experimental system that relied on 
 both collinear loci and highly selected chromosomal inversions\, highlight
 ing how demographic history and genomic architecture influence the detecta
 ble signature of local adaptation.A major limitation to conducting large-s
 cale comparative evolutionary studies is the lack of data standardization\
 , which prevents the integration of community knowledge and high-resolutio
 n environmental and genetic data. Chapter 4 addresses this by developing a
  community database for the Littorina system. This platform implements sta
 ndardized protocols for the integration of diverse phenotypic and environm
 ental data from multiple Littorina species. Likewise\, the platform also c
 entralizes the availability of associated genomic data through links to ex
 ternal repositories. This database represents a crucial tool to test compl
 ex\, large-scale evolutionary hypotheses.Collectively\, this thesis strong
 ly reinforces the fundamental importance of SGV as the raw material for su
 ccessful local adaptation\, a conclusion supported by evidence in both exp
 erimental and accidental introductions. Furthermore\, this work highlights
  the critical role of the genomic architecture—specifically chromosomal 
 inversions—in driving the predictability and effectiveness of adaptive r
 esponses. Our findings underscore how the interplay between SGV and genomi
 c architecture dictates the trajectory and detectability of evolution in c
 olonizing populations\, while simultaneously providing a necessary tool to
  advance comparative evolutionary genomics in non-model organisms.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
 ) and Zoom\, ISTA
ORGANIZER:
SUMMARY:Diego Garcia Castillo: Thesis Defense: The genomic architecture of 
 local adaptation in introduced populations
URL:https://talks-calendar.ista.ac.at/events/6179
END:VEVENT
END:VCALENDAR