TY - JOUR
T1 - Marsupials in the age of genomics
AU - Graves, Jennifer A.Marshall
AU - Renfree, Marilyn B.
PY - 2013/8
Y1 - 2013/8
N2 - Marsupials are "alternative mammals" that differ from eutherians most spectacularly in their mode of reproduction and sexual differentiation. They represent a 160-million-year-old isolate from the more numerous eutherians, making them particularly valuable for comparative genome studies that enlarge and enhance our understanding of the function and evolution of the mammalian genome. The genomes of three sequenced marsupial species are similar in size to those of mice and humans but show informative differences in base composition and repetitive elements. Small differences in gene sets and gene families between marsupials and eutherians may relate to physiological and environmental differences. Marsupial karyotypes are highly conserved in chromosome numbers, sizes, and G-banding patterns, and an ancestor with a 2n = 14 karyotype can be deduced. Marsupial sex chromosomes, partly homologous to those of eutherians, represent the ancestral therian XY pair. Epigenetic regulation of X inactivation in marsupials differs markedly from that of eutherians and has apparently retained an ancient silencing mechanism. Genomic imprinting of a smaller set of genes occurs in the marsupial placenta and, uniquely, in the mammary gland.
AB - Marsupials are "alternative mammals" that differ from eutherians most spectacularly in their mode of reproduction and sexual differentiation. They represent a 160-million-year-old isolate from the more numerous eutherians, making them particularly valuable for comparative genome studies that enlarge and enhance our understanding of the function and evolution of the mammalian genome. The genomes of three sequenced marsupial species are similar in size to those of mice and humans but show informative differences in base composition and repetitive elements. Small differences in gene sets and gene families between marsupials and eutherians may relate to physiological and environmental differences. Marsupial karyotypes are highly conserved in chromosome numbers, sizes, and G-banding patterns, and an ancestor with a 2n = 14 karyotype can be deduced. Marsupial sex chromosomes, partly homologous to those of eutherians, represent the ancestral therian XY pair. Epigenetic regulation of X inactivation in marsupials differs markedly from that of eutherians and has apparently retained an ancient silencing mechanism. Genomic imprinting of a smaller set of genes occurs in the marsupial placenta and, uniquely, in the mammary gland.
KW - Chromosome evolution
KW - Epigenetics
KW - Marsupial reproduction and development
KW - Sex chromosomes
KW - Short-tailed opossum
KW - Tammar wallaby
UR - http://www.scopus.com/inward/record.url?scp=84884312862&partnerID=8YFLogxK
U2 - 10.1146/annurev-genom-091212-153452
DO - 10.1146/annurev-genom-091212-153452
M3 - Review article
SN - 1527-8204
VL - 14
SP - 393
EP - 420
JO - Annual Review of Genomics and Human Genetics
JF - Annual Review of Genomics and Human Genetics
ER -