Photo of Jordi Altimiras

Jordi Altimiras


Reptiles have a small heart and birds have a larger heart, what has happened?


My research career has been about understanding the function of the heart in animals. Currently, my main project is the study of the evolution of the heart in birds, particularly how the heart grows and how it reacts to environmental challenges.

As an example: when a bird is placed in a harsher (read cooler) climate the heart gets enlarged. Chickens raised in cold conditions have a heart size twice as large as that of a chicken raised indoors.  This is interesting from an evolutionary perspective, but it also has relevant biomedical implications because pathological enlargement of the heart (so called cardiac hypertrophy) leads to heart failure.

Need for basic cardiology research

Cardiac pathological hypertrophy differs from the normal growth of the heart associated with exercise in humans, or with cold exposure in birds. Although we know a great deal about the problems and consequences of hypertrophic enlargement of the heart, less is known about the actual mechanisms responsible for such growth. My belief is that the basic research we carry out will be able to explain the evolutionary roots of hypertrophic growth and its genetic architecture.

Studies on the evolution of the heart have typically focused on the heart in crocodiles because it is the most ancient type of four-chambered heart (two atria and two ventricles). In my opinion, however, this approach neglects the importance of heart size in overall performance. Thus I suggest that important clues can also be found by studying the most ancient group of extant birds, the South American tinamous. Unlike its closest relatives, the ostriches, tinamous can fly and they do that with a heart that is half the size of the hearts of most other, comparable bird species.

Transformation in heart size 

Reptiles have a small heart while birds have a larger heart. What mechanisms guided that transformation? Through the study of tinamous we want to understand the evolution of reptiles into birds with larger hearts. In comparison with modern birds, tinamous are quite limited because they do not fly well and they can only do so for short periods of time. They do, however, keep a high body temperature.

Studying tinamous is an attempt to study the past in the present. Comparing physiological performance and gene expression in tinamous, crocodiles, and modern birds, we expect to find out how changes in gene expression lead to an enlargement of the heart and, consequently, an increase in its performance.

Opportunities for Student Projects

Biology students at Linköpings universitet carry out a mandatory bachelor project (so called "kandidatarbete") in their last semester of bachelor level studies, and a one-year research project as part of their master’s degree. In my research group, students have the opportunity to travel to South America with scholarships from the Linnaeus-Palme exchange program or the Minor Field Studies program. The field research projects are done in collaboration with Alvaro Garitano from the Universidad Mayor de San Andrés in La Paz, Bolivia and Roberto Nespolo from Universidad Austral de Chile in Valdivia, Chile, and the results are integrated in our group's research.



Caroline Lindholm, Jordi Altimiras (2023) Physiological and behavioral effects of intermittent fasting vs daily caloric restriction in meat-type poultry Animal, Vol. 17, Article 100849 Continue to DOI


Natasa Debeljak, Aljaz Kosmerlj, Jordi Altimiras, Manja Zupan Semrov (2022) Relationship between anatomical characteristics and personality traits in Lipizzan horses Scientific Reports, Vol. 12, Article 12618 Continue to DOI
Caroline Lindholm, Petros Batakis, Jordi Altimiras, John Lees (2022) Intermittent fasting induces chronic changes in the hepatic gene expression of Red Jungle Fowl (Gallus gallus) BMC Genomics, Vol. 23, Article 304 Continue to DOI


Amir Fallahshahroudi, Martin Johnsson, Enrico Sorato, S. J. Kumari A. Ubhayasekera, Jonas Bergquist, Jordi Altimiras, Per Jensen (2021) Effects of the domestic thyroid stimulating hormone receptor (TSHR) variant on the hypothalamic-pituitary-thyroid axis and behavior in chicken Genetics, Vol. 217, Article iyaa050 Continue to DOI


Amir Fallahshahroudi, Enrico Sorato, Jordi Altimiras, Per Jensen (2019) The Domestic BCO2 Allele Buffers Low-Carotenoid Diets in Chickens: Possible Fitness Increase Through Species Hybridization Genetics, Vol. 212, p. 1445-1452 Continue to DOI



Key information

Academic positions 

  • 2005-present. Docent. IFM. Linköping University, Sweden
  • 2002-2005. Lektor (Assistant Professor). IFM. Linköping University, Sweden
  • 2001-2002. Profesor Auxiliar Convidado (Assistant Professor). Fac.Ciências da Saude. Universidade da Beira Interior, Portugal
  • 1999-2001. Post-doctoral Fellow of the Marie Curie TMR program of the European Union. Department of Zoology. University of Göteborg, Sweden.
  • 1997-1999. Post-doctoral Fellow of the Danish Research Council. Department of Zoophysiology. University of Aarhus, Denmark.
  • 1996-1996. Lecturer “Human Anatomy and Physiology”. Department of Biological Sciences. University of Nevada Las Vegas, USA.
  • 1995-1996. Post-doctoral Fellow of the American Heart Association. Department of Biological Sciences. University of Nevada Las Vegas, USA.
  • 1990-1994. Predoctoral Fellow from the Spanish Science and Education Ministry (FPI Program). Departament de Biologia Cel.lular i Fisiologia, Universitat Autónoma de Barcelona, Spain.


Complete Curriculum Vitae (PDF)

Supervision, sample

Postdoctoral fellows

  • 2012-2013. Dr.Ann-Charlotte Svensson-Holm. Currently research engineer at Linköping University
  • 2011-2013. Dr.Isa Lindgren. Currently research fellow at Oregon Health Sciences University, USA
  • 2005. Dr.Dane A.Crossley II. Currently Assistant Professor at the University of North Texas, USA

PhD students

  • 2013-. Caroline Lindholm (Linköping University, Sweden). Main supervisor
  • 2012-. Pia Katrine Løtvedt (Linköping University, Sweden). Co-supervisor
  • 2011-. Hanna Österman (Linköping University, Sweden). Main supervisor

Master's students

  • 2014. Åsa Näsström, Andreas Calais and Johan Jonsson (LiU, Sweden)
  • 2013. Sergiy Kovtun (LiU, Sweden)
  • 2012. Shehla Irrum and Syeda Huma Zahra Naqvi (LiU, Sweden).

Honor's students

  • 2013. Camilla Lövgren, Veronika Karczmarz, Panagiotis Karalekas, Cecilia Söderberg
  • 2012. Åsa Näsström, Naomi Aira, Emma Backlund

Membership in Scientific Societies

  • Society of Experimental Biology
  • American Physiological Society
  • European Society of Comparative Biochemistry and Physiology
  • Marie Curie Fellowship Association
  • Asociación para el Avance de la Ciencia y la Tecnología en España