Dynamic evolution of olfactory receptor genes in mammals: Possible link to anatomy and ecology (Yoshihito Niimura) and
Takushi Kishida, Yoshihito Niimura
Date & Time: 
1 Dec 2017 - 3:00pm
Event Type: 
Invited Seminar
CES Seminar Hall, 3rd Floor, Biological Sciences Building

Dynamic evolution of olfactory receptor genes in mammals: Possible link to anatomy and ecology
Yoshihito Niimura

Olfaction, the sense of smell, is essential for the survival of most animals. It is used for foraging, communicating with conspecifics, and recognizing predators. Diverse odor molecules in the environment are detected by olfactory receptors (ORs) expressed in the olfactory epithelium of the nasal cavity. There are ~400 and ~1,100 OR genes in the human and mouse genomes, respectively, constituting the largest multigene family in mammals. Bioinformatic analyses using various genome sequences revealed that the numbers of OR genes vary greatly among species: African elephants have the largest number of functional OR genes ever examined, with ~2,000, while bottlenose dolphins, which have completely lost the olfactory apparatus, retain only ~10.
In my talk, I would like to introduce our recent study on the degeneration of OR genes in primate evolution, since it provides an excellent example of how anatomical/ecological factors affect the OR gene repertoire in each species. I will also briefly mention preliminary results on the OR genes in Asian elephants.

Population history of whales (and elephants) based on individual whole-genome sequences
Takushi Kishida

Speciation in the open ocean has long been studied, but it remains largely elusive how populations of highly mobile animals, such as whales, in such an open environment become reproductively isolated. Baleen whales of the genus Balaenoptera undertake extensive migrations, and there are few obvious barriers that potentially isolate their populations in the open ocean. In this talk, population history of common minke whales B. acutorostrata and Antarctic minke whales B. bonaerensis was inferred based on the whole genome sequence data of an individual, and discuss about speciation of these two species using such recently-developed genomics tools. I will also talk about very preliminary data on the demographic history of Indian elephants and presence of a bottleneck during the last glacial period.

Fungus-Farming Termites Selectively Bury Weedy Fungi that Smell Different from Crop Fungi by Lakshya Katariya et al., Renee Borges Lab

Worker castes of fungus-growing termite depositing “agar boluses” on the fungal plug of weedy
Pseudoxylaria (from the October issue of Journal of Chemical Ecology). Photo Credit: Nikhil More

Lakshya Katariya and colleagues (Renee M Borges’ lab) discover that fungus-farming termites
selectively bury the weedy fungi that smell different from crop fungi

Fresh elephants’ dung reveals stress levels in wild Asian elephants

Recent research findings by a CES Ph.D. student Sanjeeta Sharma Pokharel, Prof. Polani B Seshagiri (MRDG, IISc) and Prof. Raman Sukumar (CES, IISc) show that the stress levels and body condition of elephants varied between seasons. Wild Asian elephants were showed ‘poor’ body condition and were found to be ‘more’ stressed during resource-deficient periods. This pattern was more conspicuous in female Asian elephants.

Study by Pratibha Yadav and Renee Borges shows that insects can smell with their ovipositors

Fig Wasp

The egg laying organ of insects, their ovipositor, is usually believed to only taste via chemical receptors. A recent study by CES PhD student Pratibha Yadav and Prof. Renee Borges shows that insect ovipositor can also sense smell.

Role of Terrestrial Ecosystems in Climate Change: Tandem use of Observations, Modeling and Remote Sensing to Understand their Complexity
Dr. Ajit Govind, Kerala University
Date & Time: 
9 Dec 2016 - 10:30am
Event Type: 
CES Seminar Hall, 3rd Floor, Biological Sciences Building
Before the talk

The terrestrial biogeochemical processes are perhaps the most dynamic and complex
component of the Earth’s Climate system. In order to better understand this complex system, the
integrated use of process-based modeling, remote sensing (RS) and measurements at multiple scales
(with an ecohydrological spirit) is proposed.
At the outset, a process-based ecohydrological model (BEPS-TerrainLab V2.0) that has tight
coupling of water (W), energy (E), carbon (C) and nitrogen (N) cycles is discussed as applied to a
forested ecosystem in boreal Canada. The potential errors in the simulated C fluxes under abstracted
hydrology are presented using a numerical experiment. Further, an improved and generic model
(STEPS) is presented as applied to a patchy-landscape in southern France. Improvements made
towards the modeling of canopy radiative transfer mechanism, in addition to some issues that are
pertinent to agro-ecosystems (C4 photosynthesis, irrigation, fertilizer N etc.) are presented. In the
second part of the presentation, long-term modeling of C in the soil and vegetation is discussed from
the lessons learnt from various projects in the Canadian C Program and the AmeriFlux programs.
Some studies on the long term ecohydrological responses under climate change in the lower
Himalayas are also discussed.
Finally, large-scale ecohydrological interactions are discussed. An analysis of the recent trends
in the global vegetation is explored using long-term RS data (AVHRR). Because of the importance of
soil water in governing the global vegetation, I hypothesize a major limitation in the widely used
global estimate of terrestrial photosynthesis (MOD17A2). A modeling strategy that is being developed
to improve the MOD17A2 by incorporating soil moisture data is briefly explained. In this regard, I
also present an analysis of some global soil moisture products obtained from microwave RS (SMOSL3
and AMSRE-LPRM) with respect to a reanalysis product (ECMWF).

Speaker Bio: 
A broadly trained environmental physicist who is interested to study the various biogeochemical and biogeophysical interactions on the Earth’s surface. He was born and raised in Kerala. His academic training consists of a Bachelor’s degree in Agricultural sciences (TNAU, India, 1998), Master’s degree in Agricultural Physics (IARI, India, 2001) and Doctoral degree in ecohydrological modeling (University of Toronto, Canada, 2008). He has worked in Canada, USA, France and India and has developed two numerical models (BEPS-TerrainLab V2.0 and STEPS) that can simulate terrestrial Carbon, Water, Nitrogen and Energy cycles. He is a senior scientist at the French National Institute of Agricultural Research [INRA], but, is currently is on a long leave of absence to take a faculty position at the Univ. of Kerala under the UGC Faculty Recharge Program.

Its raining bush frogs in the Western Ghats by Kartik Shanker and SP Vijayakumar

Bush Frogs

Its raining bush frogs in the Western Ghats
Kartik Shanker and SP Vijayakumar

Should you find yourself wandering in the cloud-drenched mountains of the Western Ghats, you would be engulfed by a cacophony of frog calls. Many of these will be bush frogs, a group of miniature frogs distributed throughout south and southeast Asia. Some are so small that they can be accommodated on your thumbnail!