PROJECT SUMMARY
This proposal will study the plant monkeyflower (Mimulus) to address why telomere lengths vary between
individuals, and how that variation affects an organism’s fitness and ultimately its evolution. Telomeres are
DNA-protein complexes found at ends of eukaryotic chromosomes and have the crucial role of protecting
chromosome ends from genomic instability. Changes in the telomere length can have catastrophic
consequences for an organism, for instance in humans aberrant telomere lengths can lead to tumorigenesis
and aging-related diseases. Paradoxically, despite the potential deleterious consequences, telomere lengths
are highly variable within natural organisms indicating a potential functional mechanism maintains variable
telomere lengths within populations. Uncovering the mechanisms of telomere length regulation and
understanding the biological significance of natural telomeric variation is crucial, as it provides the framework
for understanding human telomere variation with potential relevance for understanding human predisposition to
aging and associated diseases. However, the causes and the biological consequences of telomere length
variation are poorly understood, and addressing this gap in knowledge is the long-term goal of my lab. As a
first step to achieve this goal my research has established plants as a novel system to study telomere genetics
and evolution. I discovered plant telomere lengths are associated with variation in reproductive life-history traits
(i.e. time to flowering) and adaptive evolution has shaped the genetic variants controlling the telomere length
variation. Based on these observations I propose a hypothesis that telomere length affects cellular
development by influencing stem cells in growth centers, and this ultimately has consequences for
development of the whole organism. This hypothesis fundamentally explains why telomere length varies within
and between populations. This proposal will empirically test this hypothesis by using Mimulus as a model and
take a mechanistic approach of understanding the function and evolution of telomere length variation and its
causal link with developmental growth. Because the molecular components of the telomere are largely
conserved between animals and plants, this study has the potential to uncover the molecular and evolutionary
rules of telomere function that are shared across eukaryotes. The proposed work will investigate the
mechanistic link between the telomere length and cellular development of pluripotent stem cells that
differentiate into whole plant. Work will also investigate the evolutionary consequences arising from the link
between telomere and developmental growth, examining its role in driving the adaptive evolution of telomere
regulating genes and its role in selecting for the life-history strategy in natural populations. Ultimately, this
research will establish the basic framework for understanding the molecular and evolutionary effects arising
from the telomere, with results that can have broad applicability for other organisms, including humans.