We have constructed and sequenced a cdna library from an active platypus venom gland to identify the remaining components. Tracing monotreme venom evolution in the genomics era mdpi. Body wall the skin is attached to a thick muscle layer, the panniculus carnosus. The most highly expressed genes in the echidna venom gland are shown in table 2. It consists of a venom gland on the dorsocaudal side. The gland is thought to migrate during male development. A platypus floats along the murrumbidgee river on scottsdale reserve. To humans the venom causes acute pain and last for weeks at times. A venomous mammal the platypus is a monotreme, an egglaying mammal, found only in australia.
Therefore, we set out to characterize the enzyme responsible for this activity and to ultimately determine whether orthologous isomerases and hence daminoacidcontaining peptides are found in other mammals. Rare among mammals in that it lays eggs, the male platypus also produces venom. Genome analysis of the platypus reveals unique signatures. Poison glands, which occur in the skin of many cartilaginous fishes and some bony fishes, are frequently associated with spines on the fins, tail, and gill covers. Of these, 327 showed venom gland expression in only one duplicated copy, which is indicative of venomspecific function evolution following gene duplication.
The venom produced by the male platypus can be fatal to small animals. Their study is in the journal of the american chemical society, a weekly publication. Platypuses ornithorhynchus anatinus and other monotremes occupy an. Platypus venom probably wont kill you, but it will cause swelling at the wound site and extreme pain that could last for weeks source. Platypus venom contains many novel proteins and peptides that are different from. We know today that platypus venom is a cocktail of toxins, most of which is a mixture of proteins which resemble no other to date. The spur is covered by a blunt sheath that erodes away by 9 to 12 months of age. This placidlooking male platypus has a secret weapon. The king cobra genome reveals dynamic gene evolution and. With all the action, home probably wouldnt be able to see that the males are also injecting each other with venom. Platypus venom may help in battle against diabetes. To date, few peptides in the complex mixture of platypus venom have been identified and sequenced, in part due to the limited amounts of platypus venom available to study.
The venom apparatus in the platypus is known as a crural system. Poisonous platypuses confirm convergent evolution nature. It can also produce painful spur wounds in other mammals including man. Platypus venom has been under close scrutiny since 1895 when two naturalists charles j. The platypus venom gland is seasonally active and secretes venom only during the short annual breeding season templesmith 1973.
We propose that such construction and analysis of mammalian venom transcriptomes from small samples of venom gland, in tandem with proteomics studies, will allow. Defensins and the convergent evolution of platypus and. Using this logic the low expression of echidna toxin transcripts suggests that venom production is not a key role of this gland. The platypus is the sole living representative of its family ornithorhynchidae and genus ornithorhynchus, though a number of related species appear in the fossil record. Unlocking the mystery of the duckbilled platypus venom. It consists of a venom gland on the dorsocaudal side of the abdomen, which is connected via a venom duct to the spur on each hind leg 2 fig. Venom delivery is believed to provide individuals with an advantage over conspecifics throughout the breeding season. The rna allows us to take a sample of venom gland tissue from one animal and amplify it.
Since these venomous peptides are coded in genes, they reasoned they could collect all the active genes from the venom gland tissue of an inseason male platypus, then compare the genes being expressed there with those known to code for venomous peptides in other species they might identify more of the remaining platypus venomous peptides. Pdf understanding and utilising mammalian venom via a platypus. Warren3, katherine belov4 1institute for molecular bioscience, university of queensland, qld, australia, 2school of zoology, university of tasmania, tas, australia, 3the genome institute. Recent research suggests that the spur is used during aggressive encounters between rival males. These spurs are hollow and are attached by ducts to venom glands in the upper thigh regions templesmith 1973.
The platypus is one of the few living mammals to produce venom. Martin and frank tidswell made their first account. We identified 378 pairs of monotremespecific duplicates, where at least one gene copy 100 illumina reads was one of the 5,410 proteincoding genes expressed in the platypus venom gland. The sole extant representative of the derived form of the monotreme venom system is the semiaquatic, semifossorial platypus o. The most abundant venom components in platypus venom, venom defensinlike peptides and ctype natriuretic peptides, were not identified in echidna table 3. Males use them against predators or in battles with other. Platypus venom could hold key to diabetes treatment. The venom apparatus in the platypus is known as a crural. The venom is produced in the crural glands of the male, which are kidneyshaped.
During the spring breeding season, venom is produced in the venom gland and. Pharmacologically characterized venom proteins have been found to be some of the most highly expressed genes in the platypus venom gland transcriptome. Understanding and utilising mammalian venom via a platypus. The spur on the males hind foot is connected to a venomsecreting gland. The venom apparatus is known as the crural system, because it is in the hind limb, and consists of paired crural venom glands connected by venom ducts to an extratarsal spur on each hind leg. Echidna venom gland transcriptome provides insights into the evolution of monotreme venom emily s. Males have a pair of spurs on their hind limbs that secrete venom that is active only in breeding season, supporting the hypothesis that the use of venom is for competition for mates, not for protection.
Platypus venom causes adverse effects in humans but may help treat type ii diabetes. The platypus is one of the few mammals to produce venom. Tracing monotreme venom evolution in the genomics era. Echidna venom gland transcriptome provides insights into. Male platypuses possess a hollow spur on each hind leg, which is connected via a duct to a venom gland. By looking instead at the genes that make the venom proteins, whittington needs a much smaller sample only a single venom gland from one platypus. This is a far more efficient way to figure out whats in the venom.
Platypus hunter studies the bizarre mammals venom the. Platypus venom ingredient may help treat type 2 diabetes. Besides that, as whittington knows from her childhood trips in australia, its quite difficult to catch a wild platypus. Convergent recruitment of proteins into animal venoms. Males have a pair of spurs on their hind limbs which secrete venom that is only seasonally active to. Juvenile females possess a remnant spur sheath that is subsequently lost during the first year of life, and spurs develop only in males. The defensinlike peptides isolated from platypus venom are related to the. The spurs can be wielded in defense, and the venom is potent enough to kill small animals and cause intense pain in humans if the spur penetrates the skin. Platypus venom genes resemble those found in snakes, lizards and spiders. Now scientists are reporting an advance toward deciphering the chemical composition of the venom, with the first identification of a dozen protein building blocks. Corresponding to its haematological characteristics, the blood of the platypus has been found to have a. The nonaggressive behavior of the animal during the breeding season, the structure of the spur, along with the histology of the echidna venom gland suggests that echidna venom has a vastly. The platypus is one of very few venomous mammals in the world.
To determine whether the echidna crural gland retains its ancestral venomous role, we compared an echidna inseason venom transcriptome with a platypus inseason venom transcriptome. The male platypus has a hollow spur that is connected to the venom gland however the female platypus does not have these venomous spur. Venom made by their crural glands a sweat gland coopted by evolution that. Novel venom gene discovery in the platypus genome biology full. Platypus venom ingredient may help treat type 2 diabetes the egglaying mammals evolved remarkable insulin regulation techniques which may have stemmed from fighting over females. We identified 83 novel putative platypus venom genes from toxin families, which are homologous to. We show that regulatory components of the venom secretory system may have evolved from a pancreatic origin and that venom toxin genes were coopted by distinct genomic mechanisms. It consists of a venom gland on the dorsocaudal side of the abdomen, which is connected via a venom duct to the spur on each hind leg. There is no distinct layer of subcutaneous fat as in tachyglossus, the echidnas griffiths 1978. Male platypuses possess spurs on each hind leg that are connected to paired venom glands on the dorsocau dal aspect of the abdomen to form. The platypus ornithorhynchus anatinus has always elicited excitement and controversy in the zoological world 1. The platypus has no subcutaneous fat unlike the echidna but does store fat in its tail, which makes up 40% of its total body fat.
Platypus venom shares some molecules also found in reptile venom, but researchers determined that the platypus poison capacity evolved separately source. The platypus ornithorhynchus anatinus, sometimes referred to as the duckbilled platypus, is a semiaquatic egglaying mammal endemic to eastern australia, including tasmania. Male platypuses have a spur on the inner side of each ankle that is connected to a venom gland located over the thighs. Limited role for gene duplications in the evolution of. An anatomical feature of the platypus ornithorhynchus anatinus that is seen in only one other mammal, the echidna, is that the male has a crural glandular system that produces venom that is used for defence and territorialbreeding functions. Spread across the advanced snakes is an enormous variation of fang and venom gland morphologies that arose from the ancient. The duckbilled platypus ornithorhynchus anatinus is one of the few venomous australian mammals. The platypus, a monotreme found in australia, is notable for its duckbilled face and generally unusual appearance.
Novel venom gene discovery in the platypus genome biology. Here we describe the status of current research into the venom of the platypus, a semiaquatic egglaying australian mammal, and discuss our approach to platypus venom transcriptomics. Venom is the mark of a special club, a select subset of the animal kingdom. The same hormone produced in the gut of the platypus to regulate blood glucose is also produced in their venom, researchers have found and that hormone could be. In the platypus this venom system is well developed and capable during the breeding season of inflicting wounds, but not apparently death, during territorial fighting between males templesmith 1974. We expected to see high levels of similarity between the two species but were fascinated to discover that the echidna venom gland secretion was markedly different to that from a platypus.
Schematic drawing indicating the approximate position of the platypus venom gland and erect spur. Platypus males possess a sharp spur on each hindlimb, and the spur is connected to a venom gland located in the upper thigh region. There is a welldeveloped diaphragm at the base of the rib cage home 1802a. Juvenile females possess a remnant spur sheath that is subsequently lost. The lungs of the platypus consist of two lobes on the right side and one on the left. In addition to the platypus, other mammal species that also have the ability to produce and inject venom include shrews, water shrews and solenodons. The evolutionary origins of monotreme crural glands. An australian researcher says the venom of the strange duck. Guided by this bioassay, we identified 11 novel peptides, including the heptapeptide hhisasphisproasnproargoh 1. It includes vipers, jellyfish, spiders, scorpions, centipedes, bees, cone snails, newts, platypus, and even a primate. Photophores, lightemitting organs found especially in deepsea forms, may be modified mucous glands. In this animalwised article we will share information about the venom produced by platypuses, to try and answer the question is platypus venom deadly.
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