Geoffrey Shaw

University of Melbourne | MSD · School of BioSciences

Introduction: The MAPK genes are critical for gonadal differentiation in eutherian mammals but their role in marsupial mammals is unknown. Characterisation and phylogenetic analyses of the tammar wallaby MAPK genes shows these genes are highly conserved with their orthologues in mammalian and non-mammalian species. Methods: We cultured sexually ind...

Background Genomic imprinting results in parent-of-origin-specific gene expression and, among vertebrates, is found only in therian mammals: marsupials and eutherians. A differentially methylated region (DMR), in which the methylation status of CpG dinucleotides differs between the two alleles, can mark the parental identity of imprinted genes. We...

Parent-of-origin-specific expression of imprinted genes is critical for successful mammalian growth and development. Insulin, coded by the INS gene, is an important growth factor expressed from the paternal allele in the yolk sac placenta of therian mammals. The tyrosine hydroxylase gene TH encodes an enzyme involved in dopamine synthesis. TH and I...

The imprinted isoform of the Mest gene in mice is involved in key mammalian traits such as placental and fetal growth, maternal care and mammary gland maturation. The imprinted isoform has a distinct differentially methylated region (DMR) at its promoter in eutherian mammals but in marsupials, there are no differentially methylated CpG islands betw...

The imprinted isoform of the Mest gene in mice is involved in key mammalian traits such as placental and fetal growth, maternal care and mammary gland maturation. MEST has a distinct promoter differentially methylated region (DMR) in eutherian mammals but in marsupials, while MEST was thought to be imprinted, it had no DMR. In this study, we examin...

Monotremes diverged from therian mammal ancestors approximately 184 million years ago and have a number of novel reproductive characteristics. One in particular is their penile morphology. There are differences between echidna and platypus phalluses, but both are somewhat similar in structure to the reptilian phallus. The echidna penis consists of...

MAPKs affect gonadal differentiation in mice and humans, but whether this applies to all mammals is as yet unknown. Thus, we investigated MAPK expression during gonadal differentiation and after treatment with oestrogen in a distantly related mammal, the marsupial tammar wallaby, using our model of oestrogen-induced gonadal sex reversal. High-throu...

Parent specific-DNA methylation is the genomic imprint that induces mono-allelic gene expression dependent on parental origin. Resetting of DNA methylation in the germ line is mediated by a genome-wide re-methylation following demethylation known as epigenetic reprogramming. Most of our understanding of epigenetic reprogramming in germ cells is bas...

Context With limited resources for wildlife management and conservation, it is vital that the effectiveness of management programs is maximised and costs reduced. Koala populations need to be reduced in locations where they are locally overabundant and over-browsing their food trees. Subcutaneous contraceptive implants containing levonorgestrel are...

There is increasing evidence that long non-coding RNAs (lncRNAs) are important for normal reproductive development, yet very few lncRNAs have been identified in phalluses so far. Unlike eutherians, phallus development in the marsupial tammar wallaby occurs post-natally, enabling manipulation not possible in eutherians in which differentiation occur...

Environmental endocrine disruptors (EEDs) that affect androgen or estrogen activity may disrupt gene regulation during normal phallus development to cause hypospadias or a masculinized clitoris. We treated developing male tammar wallabies with estrogen and females with androgen from day 20–40 postpartum (pp) during the established androgen imprinti...

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...

The first sign of mammalian germ cell sexual differentiation is the initiation of meiosis in females and of mitotic arrest in males. In the mouse, retinoic acid induces ovarian Stra8 expression and entry of germ cells into meiosis. In developing mouse testes, CYP26B1 produced by the Sertoli cells degrades retinoic acid, preventing Stra8 expression...

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...

Sex determination and sexual differentiation pathways are highly conserved between marsupials and eutherians. There are 2 different pathways of prostaglandin D2 (PGD2) synthesis: prostaglandin D synthase (PTGDS) and haematopoietic prostaglandin D synthase (HPGDS). PGD2 regulates the subcellular localization of SOX9 during gonadal sexual differentia...

Embryonic diapause is period of developmental arrest which requires coordination of a molecular cross-talk between the endometrium and blastocyst to ensure a successful reactivation, but the exact mechanisms are undefined. The objectives of this study were to screen the tammar blastocyst for potential diapause control factors and to investigate the...

The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal, up to 11 months, during which there is no cell division or blastocyst growth. Since the blastocyst in diapause is surrounded by acellular coats, the signals that maintain or terminate diapause involve factors which reside in uterine secretions. The nature of su...

In mammals, embryonic diapause, or suspension of embryonic development, occurs when embryos at the blastocyst stage are arrested in growth and metabolism. In the tammar wallaby (Macropus eugenii), there are two separate uteri, only one of which becomes gravid with the single conceptus at a post-partum oestrus, so changes during pregnancy can be com...

When 60-day-old tammar wallaby pouch young (Macropus eugenii) are fostered to mothers at 120 days of lactation, their growth, developmental rate and maturation of their GH/IGF axes are markedly accelerated. To determine the effect of fostering on energy intake, body composition and fat accretion, we first measured total body fat and lean mass in th...

The mammalian prostate is a compact structure in humans but multi-lobed in mice. In humans and mice, FOXA1 and SOX9 play pivotal roles in prostate morphogenesis, but few other species have been examined. We examined FOXA1 and SOX9 in the marsupial tammar wallaby, Macropus eugenii, which has a segmented prostate more similar to human than to mouse....

Maturation of the mammalian growth axis is thought to be linked to the transition from fetal to post-natal life at birth. However, in an altricial marsupial, the tammar wallaby (Macropus eugenii), this process occurs many months after birth but at a time when the young is at a similar developmental stage to that of neonatal eutherian mammals. Here...

Growth hormone (GH) is necessary to grow to normal adult size. While GH plasma concentrations are highest during early development, there is no evidence that GH influences somatic growth until after birth when GH-receptors are upregulated in peripheral tissues. The gradual decline in plasma GH during fetal life in a range of mammals suggests that n...

The marsupial tammar wallaby has the longest period of embryonic diapause of any mammal. Reproduction in the tammar is seasonal, regulated by photoperiod and also lactation. Reactivation is triggered by falling daylength after the austral summer solstice in December. Young are born late January and commence a 9-10-month lactation. Females mate imme...

The Wolffian ducts (WDs) are the progenitors of the epididymis, vas deferens and seminal vesicles. They form initially as nephric ducts that acquire connection to the developing testis as the mesonephros regresses. The development of the WDs is dependent on androgens. Conventionally, the active androgen is believed to be testosterone delivered loca...

Genomic imprinting has been identified in therian (eutherian and marsupial) mammals but not in prototherian (monotreme) mammals. Imprinting has an important role in optimising pre-natal nutrition and growth, and most imprinted genes are expressed and imprinted in the placenta and developing fetus. In marsupials, however, the placental attachment is...

New observations over the last 25 years of hormone-independent sexual dimorphisms have gradually and unequivocally overturned the dogma, arising from Jost's elegant experiments in the mid-1900s, that all somatic sex dimorphisms in vertebrates arise from the action of gonadal hormones. Although we know that Sry, a Y-linked gene, is the primary gonad...

At birth, marsupial neonates have precociously developed forelimbs. The development of the tammar wallaby (Macropus eugenii) hindlimbs lags significantly behind that of the forelimbs. This differs from the grey short-tailed opossum, Monodelphis domestica, which has relatively similar fore- and hindlimbs at birth. This study examines the expression...

The mammalian phallus arises from identical primordia in both sexes and is patterned in part by the key morphogen Sonic hedgehog (SHH). We have investigated SHH and other morphogens during phallus development in the tammar wallaby. In this marsupial, testis differentiation and androgen production occurs just after birth, but it takes a further 50-6...

Marsupials differ from eutherian mammals in their reproductive strategy of delivering a highly altricial young after a short gestation. The young, with its undeveloped organ systems completes its development post-natally, usually within a pouch. The young is dependent on milk with a composition that varies through lactation to support its growth an...

The X-linked aristaless gene, ARX, is essential for development of the gonads, forebrain, olfactory bulb, pancreas, and skeletal muscle in mice and humans. Mutations cause neurological diseases, often accompanied by ambiguous genitalia. There are a disproportionately high number of testis and brain genes on the human and mouse X-chromosome. It is s...

At birth all mammalian neonates depend on finding the milk source in order to survive. The development of mammalian young ranges from precocial to highly altricial, but olfaction plays an essential role in the milk-finding process in all mammalian species studied, along with other sets of cues depending on the development of the neonate 's sensory...

The control of reactivation from embryonic diapause in the tammar wallaby, Macropus eugenii, involves sequential activation of the corpus luteum, secretion of progesterone that stimulates endometrial secretion, and subsequent changes in the uterine environment that activate the embryo. However, the precise signals between the endometrium and the bl...

Context. Fertility control offers a non-lethal management technique for iconic yet overabundant wildlife. Slow-release hormonal implants containing deslorelin show promise for managing free-ranging populations, particularly in peri-urban reserves, but most studies have been limited to captivity. Aims.We investigated the efficacy and mechanism of de...

Background Epigenetic reprogramming is essential to restore totipotency and to reset genomic imprints during mammalian germ cell development and gamete formation. The dynamic DNA methylation change at DMRs (differentially methylated regions) within imprinted domains and of retrotransposons is characteristic of this process. Both marsupials and euth...

Two major gene families derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons were recently identified in mammals. The sushi-ichi retrotransposon homologue (SIRH) family comprises 12 genes: 11 in eutherians including Peg10 and Peg11/Rtl1 that have essential roles in the eutherian placenta and 1 that is marsupial specific. Fifteen and 1...

Mammalian embryonic diapause is a phenomenon defined by the temporary arrest in blastocyst growth and metabolic activity within the uterus which synchronously becomes quiescent to blastocyst activation and implantation. This reproductive strategy temporally uncouples conception from parturition until environmental or maternal conditions are favoura...

Marsupials have a functional placenta for a shorter period of time compared to that of eutherian species, and their altricial young reach the teats without any help from the mother. We have monitored the short intrauterine development of one marsupial, the tammar wallaby, with high-resolution ultrasound from reactivation of the 100-cell diapausing...

Vitelline blood flow, expansion of allantoic sac and endometrial movement

Supplementary File Information

Pre-attachment phase

Shell coat rupture

Climbing movements

Early cell lineage specification in eutherian mammals results in the formation of a pluripotent inner cell mass (ICM) and trophoblast. By contrast, marsupials have no ICM. Here, we present the first molecular analysis of mechanisms of early cell lineage specification in a marsupial, the tammar wallaby. There was no overt differential localisation o...

Background In marsupials, growth and development of the young occur postnatally, regulated by milk that changes in composition throughout the long lactation. To initiate lactation in mammals, there is an absolute requirement for insulin (INS), a gene known to be imprinted in the placenta. We therefore examined whether INS is imprinted in the mammar...

In mice and humans, IGF2 has multiple promoters to maintain its complex tissue- and developmental stage-specific imprinting and expression. IGF2 is also imprinted in marsupials, but little is known about its promoter region. In this study, three IGF2 transcripts were isolated from placental and liver samples of the tammar wallaby, Macropus eugenii....

Primers used in this study. (PDF)

Alignment of tammar exon 1B region with opossum exon 1 region. Opossum non-coding exon = 1–420 Tammar exon 1B = 725–1104. Alignments were performed using ClustalW and were highlighted using BOXshade 3.31. (PDF)

Nucleotide sequence of the three tammar IGF2 gene promoters. The DNA sequences of IGF2 promoters P1, P2 and P3 are illustrated in A, B, and C, respectively. Transcription start sites (TSSs) identified by 5′RACE are indicated by the arrows. ggaggag repeats are in boxes, CTCCCAAG repeats are highlighted in yellow and TGTCCC repeats are highlighted in...

GRB10 is an imprinted gene differently expressed from two promoters in mouse and human. Mouse Grb10 is maternally expressed from the major promoter in most tissues and paternally expressed from the brain-specific promoter within specific regions of the fetal and adult central nervous system. Human GRB10 is biallelically expressed from the major pro...

Background The HOX gene clusters are thought to be highly conserved amongst mammals and other vertebrates, but the long non-coding RNAs have only been studied in detail in human and mouse. The sequencing of the kangaroo genome provides an opportunity to use comparative analyses to compare the HOX clusters of a mammal with a distinct body plan to th...

The length of exon and intron of tammar 39 HOX genes (bp).

The sequences of 39 tammar HOX genes.

Repetitive elements in tammar HOX clusters.

Phylogenetic footprinting analyses ofHOXC cluster with mVISTA. mVISTA plot generated with HOXC genomic sequences from tammar, human (chr12: 52605461–52742874), mouse (chr15: chr15:102750000–102892969) and frog (scaffold_226: 269568–557892) with tammar as a reference. The information of long ncRNAs and microRNAs is same as in Figure 3. Other detail...

Phylogenetic footprinting analyses ofHOXD cluster with mVISTA. mVISTA plot generated with HOXD genomic sequences from tammar, human (chr2: 176656359–176768195), mouse (chr2: 74497085–74613489) and frog (scaffold_163: 534804–660354) with tammar as a reference. Other details as in figure Additional file 4.

Valid target positions of known miRNAs in tammar HOX clusters.

Phylogenetic relationships and high-order grouping ofHOX families from tammar and human. A representative an unrooted tree with rooting that should be considered arbitrary. Phylogenetic analysis was based on the homeodomain regions with an extension of extra 20 amino acids on both sides from human and tammar. The phylogenetic tree was constructed u...

Primers for RT-PCR.

The sequences of lncRNAs and microRNAs in tammar.

Phylogenetic footprinting analyses ofHOXB cluster with mVISTA. mVISTA plot generated with HOXB genomic sequences from tammar, human (chr17: 43960868–44165742), mouse (chr11: 96024912–96229585) and frog (scaffold_334: 483000–620000) with tammar as a reference. microRNAs miR-10a located between HOXB4 and HOXB5 is highly conserved in all species. miR-...

Newly discovered target positions of putative miRNAs in tammar HOX clusters.

Phylogenetic footprinting analyses ofHOXA cluster with mVISTA. mVISTA plot generated with HOXA genomic sequences from tammar, human (chr7:27131531–27244164), mouse (chr6:52104079–52216539) and frog (scaffold_56:1381000–1485000) with tammar as a reference. Conserved regions above the level of 70%/100 bp are highlighted under the curve, with red indi...

Interferon inducible transmembrane proteins (IFITMs) have diverse roles, including the control of cell proliferation, promotion of homotypic cell adhesion, protection against viral infection, promotion of bone matrix maturation and mineralisation, and mediating germ cell development. Most IFITMs have been well characterised in human and mouse but l...

The vomeronasal organ (VNO) detects pheromones via 2 large families of receptors: vomeronasal receptor 1, associated with the protein Giα2, and vomeronasal receptor 2, associated with Goα. We investigated the distribution of Goα in the developing and adult VNO and adult olfactory bulb of a marsupial, the tammar wallaby. Some cells expressed Goα as...

Kangaroos and wallabies have specialised limbs that allow for their hopping mode of locomotion. The hindlimbs differentiate much later in development but become much larger than the forelimbs. The hindlimb autopod has only four digits, the fourth of which is greatly elongated, while digits two and three are syndactylous. We investigated the express...

This chapter discusses that the physiology of parturition in mammals is highly diverse and almost species-specific. Rather than surveying the physiology of parturition species by species, this contribution attempts to identify mechanisms that vary widely among species and those that are well-conserved. This classical comparative approach explicitly...