Sex Determination in Birds and Mammals

Mittwoch, Ursula

doi:10.1038/231432a0

Cited by 41 publications

(12 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus the possibility exists that neither of the W-chromosomes are compatible with a hybrid genetic background in these particular species. Such a possibility is consistent with the view that the W-chromosome controls the development of the ovaries in female birds (Mittwoch, 1971). Moreover, the available data, as reviewed for both the Lonchurae (present study) and Poephilae (Christidis, in press) suggest that genic factors affecting gonadal development and not chromosomal rearrangements are primarily responsible for determining hybrid fertility.…”

Section: Relationships Between Hybrid Fertility and Karyotypesupporting

confidence: 75%

Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Christidis

1986

Genetica

View full text Add to dashboard Cite

Thirteen species of estrildid finches belonging to the Lonchurae were examined cytogenetically by G-and C-banding. The major forms of karyotypic change, both within and between species, were pericentric inversions and changes in the amount of heterochromatin. It appears that the direction of chromosome change in this lineage is towards an entirely telocentric karyotype because inversions converting a biarmed chromosome into a telocentric one only occur when all the macrochromosomes of smaller size are also telocentric. A comparison of hybrid fertility data and karyotypic differences indicates that genic factors affecting gonadal development, and not chromosomal rearrangements, are the primary influence in determining hybrid fertility. The chromosomal data was also used to clarify systematic relationships within the Lonchurae and demonstrate that the genus Lonchura as presently construed is polyphyletic.

show abstract

Section: Relationships Between Hybrid Fertility and Karyotypesupporting

confidence: 75%

Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Christidis

1986

Genetica

View full text Add to dashboard Cite

show abstract

“…Ursula Mittwoch demonstrated that at the earliest time male and female gonads can be distinguished, the testis is already larger in rats (23) and man (24). In contrast, she found that in birds the ovary-i.e., the gonad of the heterogametic sex-was faster growing than the testis (25). The transcription of sexdetermining region genes in the preimplantation embryo, which strongly implies expression since we know of no example of a gene that is transcribed but not expressed in the preimplantation embryo, may provide a molecular mechanism for this phenomenon.…”

Section: Discussionmentioning

confidence: 99%

Transcription of the sex-determining region genes Sry and Zfy in the mouse preimplantation embryo.

Erickson

Boyer

1993

Proc. Natl. Acad. Sci. U.S.A.

106

View full text Add to dashboard Cite

We have confirmed the faster growth of male preimplantation mouse embryos. We have also studied the transcription of Y chromosomal genes postulated to have a role in sex determination, using the highly sensitive technique of reverse-transcription polymerase chain reaction at these early stages. We find that two sex-determining region genes (2), is an exciting advance for studies of sex determination. The finding that 40,XY female mice (3) had a deletion in this gene (2) and the identification of point mutations in this gene in some human 46,XY females (4) were highly supportive of the postulated role of this gene in sex determination. However, the most convincing proof has been the demonstration of sex reversal in some 40,XX mice transgenic for the mouse genomic clone (5). Studies on expression of Sry have focused on its transcription in presumptive Sertoli cells in the gonadal ridge at the time of gonadal differentiation-i.e., 11.5 days (6). These authors used the We mutation to show that the transcription at that time did not require germ cells. The earliest stage studied in this report was the embryonic stage at 7.5 days postcoitus, and no transcription was found until 11.5 days (6). We find much earlier transcription-as early as the two-cell stage.There had been previous evidence of differences in gene expression between male and female embryos. Although it was somewhat controversial at first, it is now well established that the male-specific antigen (MSA, serological H-Y) is detectable on preimplantation embryos (7,8). It is clear that a "growth factor" on the Y chromosome is expressed early, since embryos separated as to early blastulation (fast developers) versus late blastulation (slow developers) are predominantly male in the first group (9). We have now confirmed this effect for the preimplantation mouse embryo by a method not requiring embryo transfer, whereas others have shown that it persists to midgestation (10, 11) and also occurs in Bovidae (12, 13). Sry or Zfy (Y chromosome-linked zinc finger protein) transcription may be related to these differences.MATERIALS AND METHODS Chemicals. Pregnant mare serum gonadotropin, human chorionic gonadotropin (hCG), and most chemicals were from Sigma. The Micro-FastTrack mRNA isolation kit was from Invitrogen (San Diego), the reverse-transcription system and "fmol" DNA sequencing systems were from Promega, and the PCR purification spin kit was from Quiagen (Studio City, CA).Animals. Animals were from The Jackson Laboratory or were bred from their stock in our colony. Twenty-one-dayold (C57BL/6J x SJL/J)F1 female mice were superovulated by interaperitoneal injections of 5 units of pregnant mare serum gonadotropin followed by S units of human chorionic gonadotropin 48 hr later and then were mated with F1 males of the same cross. The time of coitus and fertilization was assumed to be at midnight after mating.Rate of Development of Male Versus Female Embryos. Embryos were flushed from the oviducts on day 1 and cultured in vitro. They were classified as to...

show abstract

“…The origin of ESD has been discussed from 2 points of view, which are actually not incompatible. Some authors proposed that ESD may be the primitive sexdetermining mechanism (Ohno 1967, Mittwoch 1971, Jones 1983, from which ancestral state a genetic system of control (followed by sex chromosomes) would have evolved. Others (Bacci 1965, Charnov & Bull 1977 have supposed that ESD is adaptive in certain life histories by allowing control of sex in response to environmental effects on fitness.…”

Section: Introductionmentioning

confidence: 99%

Environmental sex determination in a parasitic copepod: checking heterogeneity and unpredictability of the environment

Michaud

Meeûs²,

Renaud³

2004

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

For some organisms, sex is not fixed by genotype at conception but determined later by environmental conditions encountered during development (environmental sex determination, ESD). According to theoretical models, selection should favour ESD when the environment experienced by offspring is patchy and unpredictable and affects the relative fitness of males and females differentially. In a field study, we analysed the environmental heterogeneity displayed among individuals of the sea squirt Ciona intestinalis, a host for the copepod Pachypygus gibber, which is characterised by ESD. Consistent with theoretical predictions, environmental parameters that affect sex-specifically the fitness of the parasite (food and sexual partners) vary significantly in space and time. The spatial genetic structure of populations of P. gibber in the Thau lagoon, France, was investigated from allozyme data. No differentiation was found between distant populations, indicating that the larvae disperse intensively in the lagoon. Since their environment has been shown to be heterogeneous in space, and since the mothers cannot leave the host in which they developed, we conclude that both parent and offspring have little control over the quality of the environment the offspring enters. All the conditions are thus validated to support the adaptive nature of ESD in P. gibber.

show abstract

Sex Determination in Birds and Mammals

Cited by 41 publications

References 23 publications

Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Chromosomal evolution within the family Estrildidae (Aves) II. The Lonchurae

Transcription of the sex-determining region genes Sry and Zfy in the mouse preimplantation embryo.

Environmental sex determination in a parasitic copepod: checking heterogeneity and unpredictability of the environment

Contact Info

Product

Resources

About