Periodic Reporting for period 1 - HOW2DOUBLE (The basic principles of polyploidy in plants and animals)
Reporting period: 2022-09-01 to 2025-02-28
Many organisms, including plants and some animals, have more than two sets of chromosomes. These organisms are known as polyploids. Whole-genome duplications have played an essential role in creating new species and driving evolution. There’s some evidence that polyploids might have advantages, especially when the environment is unstable. Many ancient polyploid events occurred during extreme climate shifts, and today’s polyploids often thrive in tougher environments than their ancestors. However, most new polyploids don’t survive very well.
To understand why some polyploids succeed while others fail, we look at three main questions: (1) what causes polyploidy, (2) what helps newly formed polyploids survive, and (3) how they stabilize their populations over time. This research project covers all these areas, examining the genetic and evolutionary factors involved.
We are taking a broad approach, studying both plants and animals. Our primary models are the plant Arabidopsis lyrata, found in the Northern Hemisphere, and the burrowing frogs Neobatrachus, found in Australia. Both models vary in ploidy and environmental occurrence. This study combines traditional genetics with modern genomic techniques and analyzes data from natural history collections around the world.
Specifically, we aim (1) to identify genetic and environmental factors that lead to polyploidy by examining variations in the formation of unreduced gametes, (2) to investigate how polyploids manage to stabilize their fertility through selection, and (3) to explore how polyploid populations recover after they face challenges, by looking at patterns of introgression or genetic mixing.
Understanding how polyploidy works across different species can lead to important breakthroughs in biology, agriculture, and medicine.
To understand why some polyploids succeed while others fail, we look at three main questions: (1) what causes polyploidy, (2) what helps newly formed polyploids survive, and (3) how they stabilize their populations over time. This research project covers all these areas, examining the genetic and evolutionary factors involved.
We are taking a broad approach, studying both plants and animals. Our primary models are the plant Arabidopsis lyrata, found in the Northern Hemisphere, and the burrowing frogs Neobatrachus, found in Australia. Both models vary in ploidy and environmental occurrence. This study combines traditional genetics with modern genomic techniques and analyzes data from natural history collections around the world.
Specifically, we aim (1) to identify genetic and environmental factors that lead to polyploidy by examining variations in the formation of unreduced gametes, (2) to investigate how polyploids manage to stabilize their fertility through selection, and (3) to explore how polyploid populations recover after they face challenges, by looking at patterns of introgression or genetic mixing.
Understanding how polyploidy works across different species can lead to important breakthroughs in biology, agriculture, and medicine.
Our genomic studies aimed to cover large geographical territories with different environments, for which we developed methods for accessing the full genetics of existing collections, such as herbaria and museums, for a wholesome description of natural variation. Arabidopsis lyrata, a mixed-ploidy species with diploid and tetraploid populations, is one of our models for studying the origin and establishment of whole-genome duplications. A. lyrata boasts a vast geographical distribution across the Northern Hemisphere, covering territories of mild and extreme environments. We sequenced full genomes of over 400 samples from herbarium and live collections, where we found over 30 previously unknown autotetraploid populations, which are split into two distinct lineages and originated shortly after the Last Glacial Maximum. We discovered that the persistence of A. lyrata autotetraploids across Eurasia is facilitated by the introgression of preexisting adaptive alleles. A. lyrata is also one of the progenitors of allotetraploid Arabidopsis kamchatica species spread in East Asia and North America. We show that the establishment of A. kamchatica was facilitated by the immediate transition to self-compatibility determined by standing genetic variation in the mating system of A. lyrata species-complex.
This research is focused on the fundamental mechanisms of polyploidy in evolution. We aim to learn how genetics and environment interaction explain polyploid origins, survival and success. Distinguishing the impacts of the nature of polyploid origin requires the accumulation of careful evolutionary reconstructions in different models. Understanding the overlap in challenges and solutions and the uniqueness between plant and animal systems, as well as between allo and auto polyploids, can provide a comprehensive understanding of the fundamental mechanisms restoring fertility and fitness after whole-genome doubling.