The comparative genomics of monotremes, marsupials, and pinnipeds: models to examine the functions of milk proteins

Sharp, Julie A. and Watt, Ashalyn and Bisana, Swathi and Modepalli, Vengama and Wanyonyi, Stephen and Kumar, Amit and Kwek, Joly and Collins, Rod and Lefevre, Christopher and Nicholas, Kevin R. (2014) The comparative genomics of monotremes, marsupials, and pinnipeds: models to examine the functions of milk proteins. In: Milk proteins: from expression to food. Food Science and Technology International Series. Elsevier, Amsterdam, The Netherlands, pp. 75-112. ISBN 9780124051713


Milk has many functions, ranging from the provision of factors crucial to the operation of the mammary gland and the development of the suckled young through to their protection from infection. Lactation evolved about 200 million years ago with the aplacental, egg-laying monotremes, but since that time there has been extensive adaptation to reproduction, including a large repertoire of lactation strategies. This chapter discusses three animal models with extreme adaptation to lactation, and examines the option of exploiting their comparative biology to identify milk protein bioactives that may have potential in functional foods or pharmaceuticals. The echidna (Tachyglossus aculeatus, a monotreme) has a fascinating combination of reptilian and mammalian characteristics. It retains a primitive component of reptilian reproduction in the form of laying shelled eggs, but it also has a prototherian lactation process. The tammar wallaby (Macropus eugenii, a marsupial) has adopted a reproductive strategy that includes a short gestation (26.5 days), birth of an immature young, and a relatively long lactation (300 days). The composition of milk changes progressively during the lactation cycle, and these changes in milk composition subsequently control development of the young. The tammar can also practice concurrent asynchronous lactation; the mother provides a concentrated milk for an older animal that is out of the pouch, and a dilute milk from an adjacent mammary gland for a newborn pouch young. The third study species, the Cape fur seal (Arctocephalus pusilluspusillus, a eutherian), has a lactation characterized by a repeated cycle of long at-sea foraging trips (up to 23 days) alternating with short suckling periods of 2–3 days ashore. Lactation almost ceases while the seal is offshore, but the mammary gland does not progress to involution and apoptosis.Technology platforms using genomics, proteomics, and bioinformatics have been used to exploit these models to identify milk bioactives. In addition, the availability of sequenced marsupial, dog, platypus, and bovine genomes permits rapid transfer of information to the cow to provide outcomes for the dairy industry.

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Item Type: Book Chapter (Commonwealth Reporting Category B)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 19 Oct 2017 01:08
Last Modified: 08 Nov 2022 23:19
Uncontrolled Keywords: extreme lactation, milk composition, comparative genomics, bioactive, growth and development
Fields of Research (2008): 06 Biological Sciences > 0606 Physiology > 060604 Comparative Physiology
06 Biological Sciences > 0608 Zoology > 060803 Animal Developmental and Reproductive Biology
06 Biological Sciences > 0604 Genetics > 060405 Gene Expression (incl. Microarray and other genome-wide approaches)
Fields of Research (2020): 31 BIOLOGICAL SCIENCES > 3109 Zoology > 310912 Comparative physiology
31 BIOLOGICAL SCIENCES > 3109 Zoology > 310903 Animal developmental and reproductive biology
31 BIOLOGICAL SCIENCES > 3105 Genetics > 310505 Gene expression (incl. microarray and other genome-wide approaches)
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970111 Expanding Knowledge in the Medical and Health Sciences
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