Koala Development: Difference between revisions
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* '''Artificial insemination in marsupials'''<ref><pubmed>18950846</pubmed></ref> "Artificial insemination has been used to produce viable young in two marsupial species, the koala and tammar wallaby. However, in these species the timing of ovulation can be predicted with considerably more confidence than in any other marsupial. In a limited number of other marsupials, such precise timing of ovulation has only been achieved using hormonal treatment leading to conception but not live young. A unique marsupial ART strategy which has been shown to have promise is cross-fostering; the transfer of pouch young of a threatened species to the pouches of foster mothers of a common related species as a means to increase productivity. For the foreseeable future, except for a few highly iconic or well studied species, there is unlikely to be sufficient reproductive information on which to base AI. However, if more generic approaches can be developed; such as ICSI (to generate embryos) and female synchronization (to provide oocyte donors or embryo recipients), then the prospects for broader application of AI/ART to marsupials are promising." | * '''Artificial insemination in marsupials'''<ref><pubmed>18950846</pubmed></ref> "Artificial insemination has been used to produce viable young in two marsupial species, the koala and tammar wallaby. However, in these species the timing of ovulation can be predicted with considerably more confidence than in any other marsupial. In a limited number of other marsupials, such precise timing of ovulation has only been achieved using hormonal treatment leading to conception but not live young. A unique marsupial ART strategy which has been shown to have promise is cross-fostering; the transfer of pouch young of a threatened species to the pouches of foster mothers of a common related species as a means to increase productivity. For the foreseeable future, except for a few highly iconic or well studied species, there is unlikely to be sufficient reproductive information on which to base AI. However, if more generic approaches can be developed; such as ICSI (to generate embryos) and female synchronization (to provide oocyte donors or embryo recipients), then the prospects for broader application of AI/ART to marsupials are promising." | ||
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== Taxon == | == Taxon == | ||
Revision as of 21:27, 6 June 2013
Introduction
The koala (Phascolarctos cinereus) is an arboreal herbivorous marsupial native to Australia, and the only extant representative of the family Phascolarctidae.
(Greek, phaskolos = "pouch" and arktos = "bear"; Latin, cinereus = "ash-coloured")
Koala comes from the Dharuk gula, the word is erroneously said to mean "doesn't drink"
- Links: Echidna | Koala | Platypus | Category:Koala
Animal Development: axolotl | bat | cat | chicken | cow | dog | dolphin | echidna | fly | frog | goat | grasshopper | guinea pig | hamster | horse | kangaroo | koala | lizard | medaka | mouse | opossum | pig | platypus | rabbit | rat | salamander | sea squirt | sea urchin | sheep | worm | zebrafish | life cycles | development timetable | development models | K12 |
Some Recent Findings
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More recent papers |
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This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.
More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Koala Embryology <pubmed limit=5>Koala Embryology</pubmed> |
Taxon
Taxonomy ID: 38626
Genbank common name: koala Inherited blast name: marsupials
Rank: species
Genetic code: Translation table 1 (Standard)
Mitochondrial genetic code: Translation table 2 (Vertebrate Mitochondrial)
Lineage ( full ) cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Theria; Metatheria; Diprotodontia; Phascolarctidae; Phascolarctos
Development Overview
- Adults - females reach maturity at 2 to 3 years of age, males at about 3 years of age.[4]
- Joey - a single young produced each year for about 12 years.
- Gestation - approximately 35 days, born under-developed (hairless, blind, and earless). There is a report of extended gestation.[5]
- Birth - joey about 6 mm long crawls into the the mother's downward-facing pouch.
- Pouch Development - joey remain in the pouch for about 6 months attached to one of the two available teats and feeding on milk, complete development.
- Outside of the pouch - joey then begins to explore and to consume small quantities of the mother’s "pap" (thought to come from the mother's cecum) in order to inoculate its gut with the microbes necessary to digest eucalypt leaves.
- Joey will remain with its mother for about another 6 months, riding on her back, and feeding on both milk and eucalypt leaves until weaning is complete at about 12 months of age.
System Development
The marsupial neonate at birth has a variation between the degree of development of different systems.[6]
- well-developed - digestive, respiratory and circulatory system.
- not well-developed - retains fetal excretory system with a fully functional mesonephric kidney and undifferentiated gonads and genitalia.
Oocyte
Ovarian Follicle Development
The following data is from a histological study of ovaries from adult female koalas.[7]
- primordial follicles - have a small primary oocyte surrounded by a few squamous epithelial cells
- primary follicles - have a single layer of cuboidal granulosa cells around the oocyte.
- secondary follicles - have two or more layers of granulosa cells but no antrum
- tertiary follicles (Graafian) - have many layers of granulosa cells surrounding a follicular fluid-filled antrum of variable size.
- oocytes about 140 µm in diameter (range 110–162 µm: n = 5 individuals) surrounded by a zona pellucida (ZP) about 8 µm thick, which is twice as thick as most other marsupial species.
Marsupial eggs are enclosed by a series of layers:[8]
- zona pellucida, three zona proteins (ZPA, ZPB, ZPC)
- an additional extracellular matrix coat that lines the zona pellucida also occurs in some species.
- mucoid coat
- outer shell coat.
- Links: Oocyte Development
Spermatozoa
The spermatozoa head is hook-shaped with the most of the acrosomal contents lying within a nuclear concavity. Spermatozoa nuclei show a range of morphologies and a tendency to swell after cryopreservation procedures.[9]
- Links: Spermatozoa Development
References
Reviews
<pubmed></pubmed>
Articles
<pubmed>16928207</pubmed> <pubmed>11303907</pubmed>
Books
Search PubMed
Note searches using the term "Koala" will also find papers that refer to the KOALA Birth Cohort Study, a European study not related to the Australian animal.
Search Nov 2010 "Koala development" 41 reference articles of which 0 were reviews.
Search PubMed: Phascolarctos cinereus | Koala development | marsupial development
External Links
External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.
Glossary Links
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Cite this page: Hill, M.A. (2024, May 21) Embryology Koala Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Koala_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G