Michael B Thompson

Michael B Thompson
The University of Sydney · School of Life and Environmental Sciences

About

316
Publications
39,334
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8,074
Citations
Citations since 2017
50 Research Items
2725 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400

Publications

Publications (316)
Article
Human-mediated dispersal of animals often acts to bring populations that have been separated for substantial periods of evolutionary time (e.g. millions of years) in their native range into contact in their introduced range. Whether these taxa successfully interbreed in the introduced range provides information on the strength of reproductive isola...
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Introduction Syngnathids (seahorses, pipefishes and seadragons) are among the few vertebrates that display male pregnancy. During seahorse pregnancy, males incubate developing embryos embedded in a placenta within a fleshy brood pouch, before expelling fully developed neonates at parturition. The mechanisms underpinning seahorse parturition are poo...
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The repeated evolution of the same traits in distantly related groups (convergent evolution) raises a key question in evolutionary biology: do the same genes underpin convergent phenotypes? Here we explore one such trait, viviparity (live birth), which qualitative studies suggest may indeed have evolved via genetic convergence. There are >150 indep...
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Shark placentae are derived from modifications to the fetal yolk sac and the maternal uterine mucosa. In almost all placental sharks, embryonic development occurs in an egg capsule that remains intact for the entire pregnancy, separating the fetal tissues from the maternal tissues at the placental interface. Here, we investigate the structure and p...
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How innovations such as vision, flight and pregnancy evolve is a central question in evolutionary biology. Examination of transitional (intermediate) forms of these traits can help address this question, but these intermediate phenotypes are very rare in extant species. Here we explore the biology and evolution of transitional forms of pregnancy th...
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Australian lizards are a diverse group distributed across the continent and inhabiting a wide range of environments. Together, they exhibit a remarkable diversity of reproductive morphologies, physiologies, and behaviours that is broadly representative of vertebrates in general. Many reproductive traits exhibited by Australian lizards have evolved...
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There are many different forms of nutrient provision in viviparous (live bearing) species. The formation of a placenta is one method where the placenta functions to transfer nutrients from mother to fetus (placentotrophy), transfer waste from the fetus to the mother and respiratory gas exchange. Despite having the same overarching function, there a...
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Introduction Embryonic growth and development require efficient respiratory gas exchange. Internal incubation of developing young thus presents a significant physiological challenge, because respiratory gas diffusion to embryos is impeded by the additional barrier of parental tissue between the embryo and the environment. Therefore, live-bearing sp...
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Knowledge of turtle hatchling ecology is fundamental for managing wild populations. Information on habitat selection by turtle hatchlings is particularly important to ensure that conservation programmes that release hatchlings into the wild give them the best chances of surviving to adulthood. Currently, knowledge of the ecology of turtle hatchling...
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Introduction Viviparity (live-birth) has evolved from oviparity (egg-laying) multiple times in sharks. While most transitions from oviparity to viviparity have resulted in non-placental forms of viviparity, some sharks develop a yolk sac placenta during pregnancy. The Australian sharpnose shark (Rhizoprionodon taylori) is a placental species that s...
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Citizen science has become a popular way to collect biodiversity data and engage the wider public in scientific research. It has the potential to improve the knowledge and skills of participants, and positively change their behaviour and attitude towards the environment. Citizen science outcomes are particularly valuable for wildlife conservation,...
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Humans are increasing the frequency of fish kills by degrading freshwater ecosystems. Simultaneously, scavengers like freshwater turtles are declining globally, including in the Australian Murray-Darling Basin. Reduced scavenging may cause water quality problems impacting both ecosystems and humans. We used field and mesocosm experiments to test wh...
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The temporal pattern of juvenile release by two species of viviparous asterinid sea stars that incubate their young in the gonads was documented. Parvulastra parvivipara released juveniles (400–3000 µm diameter) in 1–5 cohorts. Parents produced large juveniles (>1000-µm) irrespective of adult size. Released juveniles were larger than the retained j...
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Our understanding of the evolution of complex biological traits is greatly advanced by examining taxa with intermediate phenotypes. The transition from oviparity (egg‐laying) to viviparity (live‐bearing) has occurred independently in many animal lineages, but there are few phenotypic intermediates. The lizard Saiphos equalis exhibits bimodal reprod...
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Mammalian pregnancy involves remodelling of the uterine epithelium to enable placentation. In marsupials, such remodelling has probably played a key role in the transition from ancestral invasive placentation to non-invasive placentation. Identifying uterine alterations that are unique to marsupials with non-invasive placentation can thus elucidate...
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Embryos of the viviparous dwarf ornate wobbegong shark (Orectolobus ornatus) develop without a placenta, unattached to the uterine wall of their mother. Here, we present the first light microscopy study of the uterus of O. ornatus throughout pregnancy. At the beginning of pregnancy, the uterine luminal epithelium and underlying connective tissue be...
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Citizen science has become popular for data collection in ecology and environmental management. However, most participants in citizen science projects are only involved for a short period of time. Understanding the reasons behind this dropout rate is important for improving long term participation. Here we investigated participation rates in Turtle...
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Nonapeptides and their receptors regulate a diverse range of physiological processes. We assessed the contractile responsiveness of uteri from the squamate viviparous-oviparous species pair, Pseudemoia entrecasteauxii and Lampropholis guichenoti, as well as the bimodally reproductive species, Saiphos equalis, to arginine vasopressin (AVP). We asses...
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Sibling competition and developmental asynchrony may greatly influence the arrangement and size of offspring of marine invertebrates that care for their young. In Parvulastra parvivipara, an asterinid sea star that incubates its young in the gonads, sibling cannibalism supports post-metamorphic development. Offspring size varies within (coefficient...
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In marine invertebrates that care for their young, the number of offspring is often correlated with adult size. The number, size, and mass of progeny relative to parent size were investigated in three asterinid sea star species that incubate their young in the gonads. Cryptasterina hystera has intragonadal planktonic-type lecithotrophic larvae with...
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Facultative changes in parity mode (oviparity to viviparity and vice versa) are rare in vertebrates, yet offer fascinating opportunities to investigate the role of reproductive lability in parity mode evolution. Here, we report apparent facultative oviparity by a viviparous female of the bimodally reproductive skink Saiphos equalis-the first report...
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The fluid that surrounds the embryo in the uterus contains important nourishing factors and secretions. To maintain the distinct microenvironment in the uterine lumen, the tight junctions between uterine epithelial cells are remodeled to decrease paracellular movement of molecules and solutes. Modifications to tight junctions between uterine epithe...
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Conservation requires rapid action to be effective, which is often difficult because of funding limitations, political constraints, and limited data. Turtles are among the world’s most endangered vertebrate taxa, with almost half of 356 species threatened with extinction. In Australia’s Murray River, nest predation by invasive foxes (Vulpes vulpes)...
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The uterine epithelium undergoes remodelling to become receptive to blastocyst implantation during pregnancy in a process known as the plasma membrane transformation. There are commonalities in ultrastructural changes to the epithelium, which, in eutherian, pregnancies are controlled by maternal hormones, progesterone and oestrogens. The aim of thi...
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The uterine surface undergoes significant remodeling, termed the “plasma membrane transformation,” during pregnancy to allow for implantation of the blastocyst and formation of the placenta in viviparous amniote vertebrates. Unlike other species within the superorder Euarchontoglires, which have a hemochorial (highly invasive) placenta, kangaroo ra...
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The pace-of-life syndrome (POLS) suggests that behavioral traits are correlated and integrate within a fast–slow physiological continuum. At the fast extreme, individuals having higher metabolic rates are more active, exploratory, and bold with the opposite suite of traits characterizing those at the slow physiological extreme. A recent framework s...
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Environmentally cued hatching allows embryos to alter the time of hatching in relation to environment through phenotypic plasticity. Spatially variable temperatures within shallow nests of many freshwater turtles cause asynchronous development of embryos within clutches, yet neonates still hatch synchronously either by hatching early or via metabol...
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Mammals exhibit similar changes in uterine epithelial morphology during early pregnancy despite having a diverse range of placental types. The uterine epithelium undergoes rapid morphological and molecular change (“plasma membrane transformation”) during the early stages of pregnancy to allow attachment of the blastocyst. The domestic cat, Felis ca...
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The evolution of viviparity requires eggshell thinning to bring together the maternal uterus and extraembryonic membranes to form placentae for physiological exchanges. Eggshell thinning likely involves reduced activity of the uterine glands that secrete it. We tested these hypotheses by comparing the uterine and eggshell structure and histochemist...
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Early pregnancy is a critical time for successful reproduction; up to half of human pregnancies fail before the development of the definitive chorioallantoic placenta. Unlike the situation in eutherian mammals, marsupial pregnancy is characterised by a long pre-implantation period prior to the development of the short-lived placenta, making them id...
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Turtles face a variety of threats (e.g. habitat destruction, introduced predators) that are pushing many species towards extinction. Vehicle collisions are one of the main causes of mortality of adult freshwater turtles. To conceptualise the level of threat that roads pose to Australians turtles, we analysed data gathered through the citizen scienc...
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Reproducing sharks must provide their offspring with an adequate supply of nutrients to complete embryonic development. In oviparous (egg-laying) sharks, offspring develop outside the mother, and all the nutrients required for embryonic growth are contained in the egg yolk. Conversely, in viviparous (live-bearing) sharks, embryonic development is c...
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In mammalian pregnancy, the uterus is remodelled to become receptive to embryonic implantation. Since non-invasive placentation in marsupials is likely derived from invasive placentation, and is underpinned by intra-uterine conflict between mother and embryo, species with non-invasive placentation may employ a variety of molecular mechanisms to mai...
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Viviparity has evolved from oviparity at least 150 independent times in vertebrates. More than 80% of these transitions have occurred in squamate reptiles, where both reproductive modes are rarely seen in different populations of the same species. This condition (bimodal reproduction) is ideal for studying the physiological and morphological change...
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Human-assisted range expansion of animals to new environments can lead to phenotypic shifts over ecological time-scales. We investigated whether phenotypic changes are sex-specific using an invasive lizard (Lampropholis delicata). Pacific region (Hawaiian Islands, Lord Howe Island, New Zealand, eastern Australia). Using our knowledge of the introdu...
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Pregnancy in mammals requires remodelling of the uterus to become receptive to the implanting embryo. Remarkably similar morphological changes to the uterine epithelium occur in both eutherian and marsupial mammals, irrespective of placental type. Nevertheless, molecular differences in uterine remodelling indicate that the marsupial uterus employs...
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The uterine luminal epithelium is the first site of contact between fetal and maternal tissues during therian pregnancy and must undergo specialised changes for implantation of the blastocyst to be successful. These changes, collectively termed the plasma membrane transformation (PMT), allow the blastocyst to attach to the uterine epithelium preced...
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1.Current syndrome research focuses primarily on behavior with few incorporating components of physiology. One such syndrome is the Pace-of-Life Syndrome (POLS) which describes covariation between behaviour, metabolism immunity, hormonal response, and life history traits. Despite the strong effect temperature has on behavior, thermal physiology has...
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en Megapodes are galliform birds endemic to Australasia and unusual among modern birds in that they bury their eggs for incubation in diverse substrates and using various strategies. Alectura lathami and Leipoa ocellata are Australian megapodes that build and nest in mounds of soil and organic matter. Such unusual nesting behaviours have resulted i...
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The formation of a placenta is critical for successful mammalian pregnancy and requires remodelling of the uterine epithelium. In eutherian mammals, remodelling involves specific morphological changes that often correlate with the mode of embryonic attachment. Given the differences between marsupial and eutherian placentae, formation of a marsupial...
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The evolutionary transition from egg-laying to live-bearing in amniote vertebrates (reptiles and mammals) requires the development of a closer association between the maternal and embryonic tissue to facilitate gas and nutrient exchange with the embryo. Because the embryo is an allograft to the father and mother, it could be considered foreign by t...
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Ex situ conservation tools, such as captive breeding for reintroduction, are considered last resort to help recover threatened or endangered species. However, they may also provide alternative strategies where reducing threats directly is difficult or ineffective. Headstarting, or captive rearing of eggs or neonate animals and subsequent release in...
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Vascular endothelial growth factor A is a major mediator of angiogenesis, a critically important process in vertebrate growth and development as well as pregnancy. Here we report for the first time the expression of a rare and unusually potent splice variant, VEGF111, in vivo in mammals. This variant has previously only been found in mammals in cul...
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Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embr...
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Across a range of taxa, individuals within a species differ in suites of correlated traits. These trait complexes, known as syndromes, can have dramatic evolutionary consequences as they do not evolve independently but rather as a unit. Current research focuses primarily on syndromes relating to aspects of behavior and life history. What is less cl...
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Alterations to the basal attachment points between the epithelium of the uterus and the underlying tissue in early pregnancy affect how easily the epithelium can be invaded by the implanting embryo. Attachment points- focal adhesions- disassemble to facilitate highly invasive implantation in rats, but species with less invasive implantation, includ...
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Metabolic processes are affected by both temperature and thyroid hormones in ectothermic vertebrates. Temperature is the major determinant of incubation length in oviparous vertebrates, but turtles can also alter developmental rate independent of temperature. Temperature gradients within natural nests cause different developmental rates of turtle e...
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The evolution of new organs is difficult to study because most vertebrate organs evolved only once, more than 500 million years ago. An ideal model for understanding complex organ evolution is the placenta, a structure that is present in live bearing reptiles and mammals (amniotes), which has evolved independently more than 115 times. Using transcr...
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Urbanization is rapidly converting natural landscapes into habitats dominated by man-made structures. Urbanized areas possess a range of novel stressors such as increased human disturbance, different suites of predators, new food types and altered habitats and complexity. Species may need to adjust aspects of their behaviour to cope with these nove...
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Sex-determining mechanisms are broadly categorised as being based on either genetic or environmental factors. Vertebrate sex determination exhibits remarkable diversity but displays distinct phylogenetic patterns. While all eutherian mammals possess XY male heterogamety and female heterogamety (ZW) is ubiquitous in birds, poikilothermic vertebrates...
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Although the adaptive significance of temperature-dependent sex determination (TSD) remains a puzzle, recent models implicate a seasonal bias in offspring sex production that translates into sex-specific fitness benefits later in life. Sex-specific emergence has been linked to fitness gains in some fish, birds and reptiles, but field data supportin...
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Ecological traps are threats to organisms, and exist in a range of biological systems. A subset of ecological trap theory is the "ethological trap," whereby behaviors canalized by past natural selection become traps when environments change rapidly. Invasive predators are major threats to imperiled species and their ability to exploit canalized beh...
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The Cretaceous Sanagasta neosauropod nesting site (La Rioja, Argentina) was the first confirmed instance of extinct dinosaurs using geothermal-generated heat to incubate their eggs. The nesting strategy and hydrothermal activities at this site led to the conclusion that the surprisingly 7 mm thick-shelled eggs were adapted to harsh hydrothermal mic...
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Studies of realized niche shifts in alien species typically ignore the potential effects of intraspecific niche variation and different invaded-range environments on niche lability. We incorporate our detailed knowledge of the native-range source populations and global introduction history of the delicate skink (Lampropholis delicata) to examine in...
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Genomic imprinting is a process that results in the differential expression of genes depending on their parent of origin. It occurs in both plants and live-bearing mammals, with imprinted genes typically regulating the ability of an embryo to manipulate the maternal provision of nutrients. Genomic imprinting increases the potential for selection to...
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Viviparity (live birth) has evolved more than 150 times in vertebrates, and represents an excellent model system for studying the evolution of complex traits. There are at least 23 independent origins of viviparity in fishes, with syngnathid fishes (seahorses and pipefish) unique in exhibiting male pregnancy. Male seahorses and pipefish have evolve...
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Invited commentary on ‘VEGF and LPS synergistically silence inflammatory response to Plasmodium berghei infection and protect against cerebral malaria’ and ‘Vascular Endothelial Growth factor (VEGF) and Lovastatin suppress the inflammatory response to Plasmodium berghei infection and protect against Experimental Cerebral Malaria’ by Canavese et al.
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Variable temperatures within a nest cause asynchronous development within clutches of freshwater turtle embryos, yet synchronous hatching occurs and is thought to be an important survival strategy for hatchlings. Metabolic compensation and circadian rhythms in heart rates of embryonic turtles indicate the potential of communication between embryos...
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Abstract Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and fragmentation. Despite this, the temporal dynamics of invasions are poorly understood, with most studies focusing on a single time point, providing us with only a snapshot of the biology and genetics of the invader. We investig...
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The evolution of viviparity requires the development of mechanisms that facilitate transport of respiratory gases between mother and developing embryo. Of particular importance is maternal excretion of embryonic carbon dioxide (CO2 ), which increases as the embryo grows in size during development. The carbonic anhydrases are a family of enzymes tha...
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In environments where animals have a high probability of encountering temperatures close to their thermal limits, animals with the capacity to minimize the chances of encountering these temperatures will be advantaged. We investigated the physiological and behavioral mechanisms used by flat rock spiders, Morebilus plagusius, to avoid encountering l...
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High-throughput sequencing using targeted enrichment and transcriptomic methods enables rapid construction of phylogenomic data sets incorporating hundreds to thousands of loci. These advances have enabled access to an unprecedented amount of nucleotide sequence data, but they also pose new questions. Given that the loci targeted for enrichment are...
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Angiogenesis (blood vessel growth), a key process of mammalian pregnancy, facilitates gas exchange and nutrient transport between the mother and the embryo and is regulated by a suite of growth factors. Vascular endothelial growth factor (VEGF) is crucial to this process in pregnant mammals and potentially pregnant squamates (lizards and snakes), a...
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To understand evolutionary transformations it is necessary to identify the character states of extinct ancestors. Ancestral character state reconstruction is inherently difficult because it requires an accurate phylogeny, character state data, and a statistical model of transition rates and is fundamentally constrained by missing data such as extin...
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Cover illustration. Attachment of the blastocyst and formation of the placenta during pregnancy is dependent on structural and cellular changes occurring in the uterine epithelium. Desmosome expression decreases during pregnancy in eutherians allowing for remodeling of the uterine epitheliumand invasion of the trophoblast during implantation. In th...
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Vascular endothelial growth factor is a secreted glycoprotein that acts on endothelial cells to induce developmental and physiological angiogenesis. It has also been implicated in angiogenesis occurring in several pathologies, most notably, cancer. Alternative splicing of VEGF mRNA transcripts results in several isoforms with distinct properties de...