Gene function in Antarctic krill: determining the role of clock-genes in synchronised behavioural patterns

Lead Research Organisation: NERC British Antarctic Survey
Department Name: Science Programmes

Abstract

Antarctic krill form an important part of the oceanic ecosystem, acting as predators on plankton and as a food source for a variety of animals including fish, sea birds and aquatic mammals. They migrate in a predictable manner each day, moving to the surface at night to feed and to greater depths during the day to avoid visually guided predators. Krill also synchronise their spawning and moulting cycles to maximise reproductive success. It is not known how these cycles are controlled, but it is likely that they are regulated by 'clock' genes. The circadian clock is an inbuilt mechanism by which the body controls many aspects of behaviour and physiology that oscillate with a 24-hour period, including the sleep-wake cycle, metabolic functions, and activity rhythms. The molecular basis of these cycles was originally described in fruit flies but has since been demonstrated in all animals investigated thus far. Interestingly, the circadian clock maintains the same general design but with remarkable species-specific differences. In addition to the circadian timekeeper, other clock mechanisms exist that control different types of periodicity, such as inter-tidal and lunar cycles, although their molecular architecture is still unknown. The aim of this project is to describe for the first time how daily migrations and monthly spawning-moulting cycles of krill are controlled by clock genes. This will involve a series of behavioural observations, to describe locomotor activity under controlled conditions, and molecular investigations to identify the clock genes associated with the daily and monthly rhythmic phenotypes and their pattern of expression. It has recently been shown that the abundance of krill has dramatically decreased in the Antarctic Ocean over the last 80 years and that this decline is correlated with a reduction in the extent of the sea ice due to global warming. In view of the importance of the species and the apparent threat from changes in climate, it is necessary that we fully understand krill behaviour so that we can monitor how they adapt to climatic changes. In particular, regular recruitment to the stock is necessary to maintain population levels so an understanding of the reproductive cycle is essential. In our work we will use both standard and state of the art methodologies and create new resources that we will make available to the scientific community. It is likely that other pelagic crustaceans have close sequence similarity with homologous krill genes. This will enable others to build on our work, both in the pursuit of scientific aims and also in relation to the farming industry.

Publications

10 25 50
 
Description We have identified the genes that constitute the circadian clock of krill. We have measured their expression and developed a model of their function.
We have generated resources. Initially we have developed a collection of sequences aligned on a small glass slide. That is called a microarray and we have used it to understand how genes are expressed under different conditions. More recently, we have sequenced all the genes expressed in the head of this animal across the day and built a searchable database. This is not public yet. When it will been finished and made public it will help other researchers interested in krill in identifying relevant genes.
We have described, using our microarray, the changes in gene expression that occur as a result of important physiological phenomena. For instance, we now know which genes are activated or silenced during the monthly cycle of moulting/hardening of the cuticle. Additionally, we have identified the changes in gene expression that correlate with the annual cycle of growth/quiescence.
Exploitation Route Our findings and the resources we have generated will help other researchers interested in the ecology and biology of krill. In particular our database will provide a point of entry to sequence information. Furthermore our study of the circadian clock of krill will be of interest to those studying comparative chronobiology
Sectors Environment

 
Description krill is a charismatic species, which reports on the health of our planet. We use our findings to inform outreach activities aimed at school children and the general public
First Year Of Impact 2007
Sector Environment
Impact Types Cultural

 
Title Krill database 
Description whole head RNAseq was annotated and used to produce a database not yet released 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact we aim to publish this database within a year 
 
Description An Introduction to biological clocks 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Big Bang at Leicester Grammar School, Leicester Grammar School, 25 February 2017, Leicester, UK
Year(s) Of Engagement Activity 2017
 
Description Big Bang at Leicester Grammar School 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact presentation on the circadian clock and its impact on humans and the natural world. People who attended understood the importance of the circadian clock, its impact on health and wellbeing and how to look for sign of the clock in every day life
Year(s) Of Engagement Activity 2017
 
Description Big Bang event at Leicester Grammar School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Schools
Results and Impact The hands onb activity we presented sparked lots of interests on Genetics and use of fruit fly for medical or fundamental research from parents and pupils

We were asked to take part the following year
Year(s) Of Engagement Activity 2015
 
Description Dynamic DNA Day 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Schools
Results and Impact every year 600 pupils and their teachers experience a Genetic Journey that many will always remember.

every year more school ask to take part that we can possibly accomodate
Year(s) Of Engagement Activity 2006,2007,2008,2009,2011
URL http://www2.le.ac.uk/departments/genetics/genie/outreach/dynamic-dna
 
Description Leicester Grammar Junior School visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Schools
Results and Impact We presented a talk on circadian rhythms and the use of Drosophila as a model system to about 61 year 5 & 6 pupils. We showed the flies and how we measure circadian rhythms in activity/rest. We talked about chronotypes and how we can assess them in humans. We had a drawing competition, a 'fly race' competition and a discussion at the end

The visit was considered positive by 15 and very positive by 31 pupils. Instead 15 pupils did not enjoy it. The science teacher was very impressed and we werer asked to contribute another project in March/April 2015
Year(s) Of Engagement Activity 2014
 
Description Loughborough Grammar school visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact About 50-60 years 11-13s pupil attended the lecture which was very well received

increase interest from pupils
Year(s) Of Engagement Activity 2014
 
Description Measuring circadian rhythms 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact stand with multiple acitivities and examples on how to measure circadian rhythms. Very good turnout of people who asked many questions about the circadian clock, sleep and how improve their sleep/wake cycle
Year(s) Of Engagement Activity 2016
URL https://nearme.thebigbangfair.co.uk/Event/?e=2520
 
Description School visit (Oundle) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact About 60-70 sixth form students attended a lecture to inform them on the circadian clock

There was great interest about the subject and the talk was followed by an interview to be broadcasted on the school radio
Year(s) Of Engagement Activity 2006,2014
 
Description The clock within us 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Public Lecture: The clock within us. Uppingham School, 15 November 2017, Uppingham, UK
Year(s) Of Engagement Activity 2017
 
Description Wurzburg open day 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Open day in Wurzburg, Germany together with our European collaborators. The workshop showed the importance of rhythmicity and photoperiodism in humans and the natural world. The attendees demonstrated increased interest and awareness after attending our activities.
Year(s) Of Engagement Activity 2017
 
Description York Festival of Ideas 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presented a lecture on the importance of our body clock for health and wellbeing. This was in the context of a symposium on sleep and the body clock. The participants left with increased awareness about the subject.
Year(s) Of Engagement Activity 2016