http://evolution.berkeley.edu/evosite/evo101/IIIC6cComplexity2.shtml Overview of Lecture: 11/11 Development Read: Text ch 46 & 47 (review 18.4 & 21.6) Bullet Points: • development • oogenesis • ovulation • fertilization • signals & cell fate mapping • stem cells • sonic hedge hog • hox genes and segmentation • immunity and placental mammals • genomic imprinting • sex determination • mosaic XX in calico cats & women{age of egg & sperm of 40 yr old couple?} puberty fetal developmentThese tests measure the increase in LH in urine, at the time of ovulation. But there are cues ... Concealed ovulation makes the rhythm method of contraception ‘probabilistic.’ composite faces of women at highest & lowest oestrogen levels - which do you find more attractive? (Image: Miriam Law Smith) Martie Haselton October 10, 2007 By Abigail Goldman Science says lap dancers send 'signals,' rake in cashhttp://www.ucalgary.ca/UofC/eduweb/virtualembryo/db_tutorial.html Plan B® {estrogen and progestin} prevents pregnancy by stopping the release of an egg from the ovary, ... may also prevent the fertilization, and/or attachment of fertilized egg to the uterus. ... will not affect a fertilized egg already attached to the uterusThe zygote's first cell division begins a series of divisions, with each division occurring approximately every 30 hours. Role for sperm in spatial patterning of the early mouse embryo. K Piotrowska & M Zernicka-Goetz 2001 Nature 409,517-521 we show that the sperm entry position (FC) predicts the plane of initial cleavage of the mouse egg and can define embryonic halves of the blastocyst. The first cleavage of the mouse zygote predicts the blastocyst axis BERENIKA et al. Nature 434, 391 - 395 (17 March 2005); ... the first cleavage contributes to breaking the symmetry of the embryo, generating blastomeres with different developmental characteristics. {How does each cell determine “fate:” top-bottom, front-back, right-left?}Special Issue: Germ Cells The Transitioning Germ Line Beverly A. Purnell and John Travis Science 20 April 2007: 387. PDF »Lance Davidson C&R Fig 18.15b~6 days post-ovulation … the blastocyst enters the uterine cavity. {meanwhile – back at the uterus ...}http://www.ucalgary.ca/UofC/eduweb/virtualembryo/db_tutorial.html To continue this narrative for 9 months, go to …… the common ancestor to fruit flies and mice had one {HOM} gene … There are 4 copies of the Hox clusters in vert’s. see Fig 21.17 http://evolution.berkeley.edu/evosite/evo101/IIIC6cComplexity2.shtml ©American Scientist http://www.amsci.org/amsci/captions/captions97-03/Erwin-cap9.html?138,96Embryo & placenta at 7 weeksThe ‘Holy Grail’ of reproductive immunology has been to elucidate the fundamental processes that explain fetal survival in all mammalian species.Brain development: The most important sexual organ New evidence suggests that the brain begins to develop differently in males & females much earlier than was thought — before sex hormones come into play. Nature 427, 390 - 392 (29 January 2004) Sexually dimorphic gene expression in mouse brain precedes gonadal differentiation. Dewing et al. 2003 Molecular Brain Research 118:82-90. ... identified {51} genes differentially expressed between male and female embryonic mouse brain before any embryonic gonadal secretion has taken place.Adult male sexual behavior in mammals requires the neuronal organizing effects of gonadal steroids during a sensitive perinatal period. During development, estradiol {a metabolite of testosterone} differentiates the rat preoptic area (POA), an essential brain region in the male copulatory circuit. Here we report that increases in prostaglandin-E2 (PGE2), resulting from changes in cyclooxygenase-2 (COX-2) induced by perinatal exposure to estradiol, are sufficient to organize the crucial neural substrate that mediates male {rat} sexual behavior. {↑ estradiol → ↑ COX-2 → ↑ PGE2 → ↑ POA dendritic spines → ↑ “male behavior”}{regressed facial deformation on 2D:4D; 50 men, 56 women} Shape regression of facial landmark coordinates upon 2D:4D ratio {esp right hand} for both male and female faces shows that some characteristics which are considered typically ‘male’ correspond to low 2D : 4D ratios, whereas some typically ‘female’ features correspond to high 2D : 4D ratios. A recent study ... Lutchmaya et al. (2004) obtained radioimmunoassays of foetal testosterone (FT) and foetal estradiol (FE) from routine amniocentesis. They measured 2D:4D ratios at age 2 years and found a negative correlation with FT/FE ratio independent of sex. We expected a low 2D:4D (as a result of high T) to correspond to a somewhat more robust (‘male-like’) facial shape, whereas high 2D:4D (high E) could correspond to a more gracile (‘female-like’) facial shape.The results indicate that females exhibit (1) a preference for a male face on the masculine side of average, (2) a shift toward a more masculine male face preference during the high-risk phase of their menstrual cycle {-29 frames} The results are interpreted as support for a hormonal theory of facial attractiveness, whereby perceived beauty depends on an interaction between displayed hormone markers {masculinity} and the hormonal state of the viewer. 1200 High salivary testosterone is linked to masculine male facial appearance in humans. Penton-Voak & Chen 2004 Evol & Human Behav 25 (4): 229-241 Preferences were measured using a 1200 frame QuickTime movie that was designed to systematically modify a facial image from an extreme male (0) to an extreme female configuration (1200). {masculine face (& 2/4th digit length) associated w/ testosterone} Mate choice decisions: the role of facial beauty Johnston VS 2006 Trends in Cog. Sci. 10:9-13In turn, the X developed a way to inactivate - silence - most of the genes on one of the two Xs in females, so that males and females would in large part have the same dosage of gene products. Early in female development, cells randomly choose either the maternal or paternal X to be the active X chromosome. The other one then