Linked Life Data

2626060

Source:http://linkedlifedata.com/resource/pubmed/id/2626060

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-4-11
pubmed:abstractText
In the conventional model of sex differentiation in placental mammals, a switch is envisaged to steer the indifferent gonad into the path of either testicular or ovarian development. The immediate cause of the switch is thought to be the presence or absence of Sertoli cells, which in turn is controlled by the presence or absence of the testis-determining factor on the Y chromosome (TDF in humans, Tdy in mice). Quantitative investigations indicate, however, that the rate of growth of XY gonads is faster than that of XX gonads before the formation of Sertoli cells, and furthermore, that XY embryos develop faster than XX embryos long before the formation of gonadal ridges. Since the genetic constitution of the sex chromosomes appears to manifest itself from the earliest embryonic stages onwards, the concept of indifferent gonads being switched into alternate pathways becomes inappropriate. A model is proposed in which gonadal differentiation depends on developmental thresholds: the formation of Sertoli cells needs to occur by a particular stage in time in a sufficiently developed gonad, failing which the gonad will enter the ovarian pathway. While TDF is the principal factor enhancing the rate of gonadal growth, other factors which influence development rates can modulate the probability of a gonad becoming either a testis or an ovary.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-5193
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
137
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
445-55
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Sex differentiation in mammals and tempo of growth: probabilities vs. switches.
pubmed:affiliation
Department of Genetics and Biometry, University College London, England.
pubmed:publicationType
Journal Article