Lean mass increased sig-nificantly in the exercise group compared with baseline (P # .01)and the usual care group (P , .001). At follow-up, all body com-position variables remained significantly improved in the exercisegroup compared with baseline (P , .001
interesting how we are looking at body composition, cool if looked at cardiorespiratory fitness
After 5 minutes of quiet sitting, blood pressurewas measured by using the arm contralateral to the affected breastwith an automated sphygmomanometer
interesting to measure blood pressure in one sitting? Usually will be elevated in this setting, white coat syndrome
Exercise improves individual components ofmetabolic syndrome in survivors of breast cancer7-9;however, consensus is lacking that it improvesmetabolic syndrome as a collective entity, partic-ularly in high-risk survivors of breast cancer—racial and/or ethnic minorities with obesity
interesting, obesity often occurs here because of lack to proper food/exercise
sarcopenic obesity
characterized by the combination of obesity, defined by high body fat percentage, AND sarcopenia, defined as low skeletal muscle mass accompanied by low muscle function
Fig. 3.
ogether, these results suggest that inhibition of OGT promotes PD-L1 traf- ficking from early endosomes to late endosomes and lysosomes, consistent with the accelerated degradation of PD-L1
Fig. 2.
Taken together, these results suggest that OGT inhibition sup- pressed tumor growth in a manner dependent on CD8 + T cell activity
Fig. 1.
Together, these data suggest that OGT plays a role in tumor immunity during the tumor progression
Usewar metaphors with caution; they are an ethical minefield
war metaphors also seem as though they can narrow the treatment options for patient, explore alternative medicine etc.
we havenow demonstrated for the first time that patients with PTSD ex-hibit greater vascular a1AR sensitivity, as evidenced by a lowerED50 for the selective a1AR agonist PE.
lower Ed means increased sensitivity
elective a1AR agonist, phenylephrine
bids to and activates receptor
11
at pH 0 will have fully protonated form, as increase pH deprotonate one group, lower concentration of fully protonated form, while increasing concentration where carboxyl grpup deprotanted, where cross at blue and green pKa amino group
7
drawn at pH 7
Wheninvestigating the transition between the twoarchitectures, we noted that mosquitoes, whichdisplay type-I features
when have full set of condensin II subunits they will have territory organization,
ig. 1
chromosome territories --> intrachromosomal features telomere-to-centromere axis --> intrachromosomal and inter telomere clustering --> intra and inter centromere clustering --> intra and inter
Early studies focused on histonepost-translational modifications(Barski et al. and Mikkelsen et al.) andtranscription factors (Johnson et al.and Robertson et al.
possible resources to look into to expand what is said in text, look for how they did it before, how they changed, and how that advanced the field
Our method is currently limited by the inability to identify candi-dates that contain introns but can be expanded to include modelsof introns in fungi.
limitation
test the ability to identify novel phero-mones, we verified that deletion of all copies of the candidate far-nesylated pheromone of Yarrowia lipolytica (whose last commonancestor with S. cerevisiae existed more than 300 million yearsago) prevented mating of the a cells of this species.
cool, are they actually performing a hypothesis driven experiment after the computational to see if they truly did what they were searching for?
Overall,we find known or candidate pheromone genes in 241 of332 mined genome
trying to identify pheromone genes
We built a computational pipeline to identify farnesylatedfungal pheromones in sequenced genomes.
purpose
look forhomologs of known pheromones in sequenced fungal ge-nomes
alternative to the above approach
Since then, pheromones have beenbiochemically isolated and characterized in laboratory yeasts,filamentous fungi, and crop pathogens by isolation from extra-cellular medium, 2,9,17,18 but this approach depends on discov-ering the environmental conditions that stimulate mating and ob-taining sufficient material to determine the pheromone’s peptidesequence
limitation
Finding thepheromones of economically important yeast will help to under-stand and control their mating as well as shed light on the evolu-tion of these molecules and the receptors that recognize them
importnace of the research
we identified strong candidate pheromone genes in241 genomes, covering 13 clades that are each separated from each other by at least 100 million years,the time required for evolution to remove detectable sequence homology among small pheromone genes.For one small clade, the Yarrowia, we demonstrated that our algorithm found the a-factor genes: deletingall four related genes in the a-mating type of Yarrowia lipolytica prevents mating
conclusions
overcome this problem
problem is short sequences and modest conservation of peptide pheromones make it hard to detect homologous sequences
) Project is to enable the scientific and medical communities tointerpret the human genome sequence and apply it to understand human biology and improve health. T
goal
GC (%)
how much genome is G and C compared to A and T
Thus, we reasonedthat low-cost de novo WGS can be applied directly after ITS sequencing.
logical reasoning/ hypothesis?
Together, these data indicateda differential reliance on ASCT2 activity across breast cancer celllines, whereby only basal-like cells required ASCT2-mediatedglutamine uptake for cell growth.
figure 1 conclusion
levels of glycolytic metabolite
early phases of glycolsis
AR-C155858 (SR13801)
what we are using
Myc directly and selectively activates MCT1 tran-scription and that elevated MCT1 levels are a hallmark ofhuman malignancies with MYC or MYCN involvement. Notably,we show that blocking MCT1 function rapidly disables glycol-ysis, leading to reductions in ATP and glutathione (GSH) levels,and that cotreatment with metformin, which forces the gly-colytic phenotype, augments the in vivo efficacy of MCT1inhibitors against MYC-expressing malignances.
conclusions
nude mice
compromised immune system, accept tumor more readily
xenograft growth
transplant
All these data indicate that WZB117, a novel Glut1inhibitor, is effective both in vitro and in vivo in inhibitingcancer cell growth and can serve as a prototypicalcompound for the further development of Glut1 andglucose transport inhibitors as a new group of anticancertherapeutics.
conclusion
Both ATPreduction and senescence were described for the first timeas potential anticancer mechanisms of Glut1 inhibitors
novelty/innovation of their study
enescence
aging
Additional but presently unknown mechanism may beinvolved in the regulation of pRb and cell-cycle arrest inA549 cells treated with WZB117.
gaps
other cellgrowth, survival, and cell death processes were examinedin WZB117-treated cancer cells to identify molecular par-ticipants and consequences of the treatment.
figure 5 purpose
fter identifying and characterizing some of the bio-logic and biochemical changes in cancer cells related toglucose transport and glucose metabolism
figure 4 purpose
Oligomycin, a specific mitochondrial inhibitor, didnot reduce cell proliferation rate at a concentration of50 nmol/L (data not shown)
why data not shown?
The possibility of theinvolvement of other mechanisms such as AMP-activatedprotein kinase (AMPK)/mTOR signaling–mediated arrestof protein synthesis cannot be ruled out
gaps in study
Fig. 3B and C)
inhibited
RBC
red blood cells
Fig. 1C
?
Figure 1
no title?
sizes of the compound-treated tumors were onaverage more than 70% smaller than those of themock (PBS/DMSO)-treated tumors
conclusion from figure 2
whether WZB117 inhibits cancer growth in animal tumormodels
question for figure 2
showing the anticancer activity of WZB117 incultured cancer cells
conclusion from figure 1
This study was done to determine the anticancerefficacy in vivo and identify the anticancer mechanism ofthe inhibitors using the compound WZB117.
Purpose
RBC and RBC-derived vesicles were prepared usingpublished protocols (22) with minor modifications
?
Protein target studies II: docking studies
?
Anaerobe Gas Generating Pouch System with indicator(BD GasPak EZ). The pouch formed an oxygen-free envi-ronment in which the compound-treated cells were incu-bated for 24 hours.
depriving cells of oxygen
Caspase
what is the importance of Caspases
The effect of BCH and the mechanism of BCH on cell growth suppressionin cancer cells
purpose
(A)
Consequently, we are able to identify sex-biased gene expres- sion that does not derive from sex differences in cell type abundances. We next modeled sex bias effects across tissues. We discovered a total of 13,294 differentially expressed genes [sex-biased genes; local false sign rate (LFSR) ≤ 0.05], with 473 to 4558 genes discovered per tissue, rep- resenting 1.3% to 12.9% of all tested genes, respectively
Placental mammals may have therefore evolved random X inactivation to alleviate the burden of maternal X-chromosome mutations.
?
In Rett's syndrome, for instance, females that carry a mutated copy of the MECP2 gene on the maternal X are able to survive (although with variable symptoms), because the paternal X has a normal copy that remains active in some cells
because the X with the mutated is inactive?
ecreased expression of SOX9
preliminary data
Transfec-tion
the introduction of nucleic acids into eukaryotic cells, or more specifically, into animal cells.
responds rapidly and strongly to Kdm6b knock-down at the very beginning of the temperature-sensitive period
Dmrt1...
Kdm6b was up-regulated at 26°C
male producing temperature
ong half-life greater than 12 h
pSTAT3
tress response correlates with changes in alternative splicingof Jumonji-family histone modifiers, suggesting a relationshipbetween cellular stress and sex-specific gene expressionchanges
interesting
central to environmental sex determination and sex changein reef fishe
cortisol
hanges in methylation at Dmrt1caused by temperature exposure were heritable and capableof over-riding chromosomal sex in the next generation
causative role of methylation
TSD
temperature-dependent sex determination
theca/Leydig
steroidogenic cells
granulosa/Sertoli
somatic cells
future oogonia or spermatogonia
germ cells
mammals seems to be to maintain male fate
DMRT1
threshold is reached sufficient to maintain andstabilize one pathway and repress the alternative pathway.
alternative explanation to metaphors we have seen
how a sex determination pathwaycan be engaged and stabilized without an inherited genetic determinant.
central question of paper
sex determination is a synthesis of manymolecular events that drives a community of cells towards a coordinatedtissue fate.
like this definition of sex determination
Due to the infertility of human females heterozy-gous for FOXL2 mutations, the homozygous loss-of-functionphenotype has not yet been reported
?
As shown here, the maintenance of female gonadal sexrequires continuous expression of FOXL2 to suppress maledevelopment
usually female is described as the default, now seeing that male is described as the default
Like Yin and Yang,
funny metaphor
Foxl2/
paper added this
cell typ
cell autonomy, gonad determination does not determine everything in the body
Why Dmrt1 mutants are feminized only after birthremains unclear.
possible research question
oestrogens, which are essential for ovariandevelopment in many vertebrates;
hormones
Sex determination can be viewed as a battle for primacy in thefetal gonad between a male regulatory gene network in whichSryactivatesSox9 and a female network involving WNT/b-catenin sig-nalling
opposes 20th century assumptions
Giventhe importance of R-spondin1 and Wnt4acting via β-catenin in establishing theembryonic ovary, it would be of inter-est to conditionally delete this path-way in adult ovaries to see whether thegonads also show ovary to testis trans-differentiation. In other words, is thiseffect solely mediated by Foxl2, or areother factors of equal importance alsoinvolved?
possible research question????
deletion of Foxl2 in the adultovary is sufficient to induce transdiffer-entiation of the ovary into a testis
contradicts terminal differentiation
activation of Sox9 bySry leads to the differentiation of thesupporting cell lineage into pre-Sertolicells.
male
ovar-ian development occurs in the absenceof Sry,
still this 20th century assumption
In all mammalianembryos, the gonad is “bipotential,”that is, it can form either an ovary ora testis.
definition of bipotential gonad
he germ-line theory had experimentalsupport from a large number of different or-ganisms.
eugenics
He obtained DNAsamples from unusual clinical cases in whichindividuals with two X chromosomes hadbeen designated as males (XX males) andones with an XY chromosomal constitutionhad been designated as females (XY fe-males)
?
can the nucleus of a fully differen-tiated cell, if placed in an undivided egg cell,direct the development of a complete andwell-formed new organism, or as they say inthe trade, do nuclei from differentiated cellsremain totipotent?
research question
We are vertebrates because our motherswere vertebrates and produced eggs of thevertebrate pattern; but the color of ourskin and hair and eyes, our sex, statureand mental peculiarities were determinedby the sperm as well as by the egg fromwhich we came
interesting, I feel like this is finally putting more emphasis on the female
The nucleusmay contain genes, but if all cells contain thesame set of genes, how indeed could differ-ent cell types arise during embryonic devel-opment?
answer is a highly complex and differentiated egg cytoplasm
he relative roles of the cellnucleus and cytoplasm in heredity.
what is it ?
The potential applications to humans cannotbe that far off.
a bit scary
specific base sequences in aDNA molecule, which is in higher organismsorganized into complex arrangements of pro-tein and nucleic acid called chromosomes.
definition of gene
The essay is divided into three parts
three parts to his 'ideology'
The basic assumption of scholars in this areais that scientific research forms an integralpart of our cultural, social, and political sys-tems.
assumptions of the field "social studies of science"
I will discuss the devel-opment of two central concepts in develop-mental biology - differential gene expressionand the continuity of the germ line; I arguethat social and political factors combinedwith particular experimental results to shapethe ideas which have come now, in the lasthalf of the 1980sto be accepted into the bio-logical canon.
connection between science and society, how science influences society and how society influences science
Now finally the father'sheirs, the "hip, young gunslingers of moderndevelopmental biology" have returned to res-cue the stunted offspring and help it, withthe heavenly blessing of the Father, to growto manhood.
interesting metaphor
(A)
Hypothesis: This figure is highlighting the outcomes that resulted from different combinations of DMRt1 and E2 in chickens. The hypothesis of the paper was that DMRT1 plays a key role in sex determination and essential for testis development and the production of estrogen is important in sex determination and is linked to DMRT1 expression. Methods: DMRT1-Mutant birds were generated using a surrogate host. These DMRT1 knockout chickens were generated using CRISPR-Cas9 to target the DMRT1 gene in cultured chicken primordial germ cells. ZD+ZD- and ZD+ZD+ are male chickens and ZD+W and ZD-W are female chickens , with the - indicating DMRT1 knockout. These genotypes were the result of crossing a wild type hen with a male chicken heterozygous for functional DMRT1. The effects of blocking estrogen synthesis (E2) on gonadal development where assessed by injecting eggs with an inhibitor of aromatase activity (fadrozole), indicated by FAD. The then looked at the presence of medullary sex cords and cortex development. Results: For the DMRT1 column, the ++ indicates 2 copies the + indicates 1 copy and the - indicates 0 copies. For the E2 and cortex column the + indicated present and the - indicates absent. The medulla column is looking at the development of the medullary sex cords into ovary or testis. Conclusions: This figure helps support the finding of the whole paper, which are the DMRT1 dosage is the driving factor of sex determination, and that gonadal hormones have little to no effect on external secondary sexual characteristics. The loss of a single copy of DMRT1 in male birds results in ovarian rather than testicle development and give proof of a DMRT1-dependent dosage-based mechanism of sex determination in birds. Connection to Arnold 2012: The theory that is discussed as incorrect in the Arnold paper is also proven wrong in this paper. The theory of sex determination is that 'the sexual phenotype of individuals is dependent on the gonad: male and female somatic cells and tissues are initially sexually indifferent and sexual dimorphism is imposed by the type of gonad that develops.' This places the differentiation of the gonads at the center of sexual determination. However; in this paper explaining avian sex determination, we see that gonads and their hormones have little or no effect on external secondary sexual characteristics.
Our analysis shows that DMRT1 is the key sex determinationswitch in birds and that it is essential for testis development, butthat production of estrogen is also a key factor in primary sexdetermination in chickens, and that this production is linked toDMRT1 expression
results
applied CRISPR/Cas9 to isolatedchicken germ cells that were injected intosurrogate embryos. Those embryos hadbeen genetically modified such that theylacked their own germ cells, and this greatlyenhanced the rate of germline transmission,in itself a highlight of the pape
methods
using genome editing to pre-cisely inactivate one copy of DMRT1 inotherwise genetically male (ZZ) chickens
ioannidis took one step further
and expression of ovary marker proteins,such as FOXL2 and aromatase
results
his resulted in‘feminisation’ of the gonads in genetic maleembryos, featuring ovarian-like structure
results
romosomal sex directs theembryonic gonads to form ovaries ortestes, which then secrete hormones tofeminise or masculinise the rest of thebody.
long held belief in animal biology
The mole
Central question: Why and how to ovotestes develop in female moles? not very hypothesis driven, but had some preconceived ideas based on other work in mammals, genes already known to have roles in sex differentiation
focus on regulatory regions, ovary part vs. testes, some relationship there worth considering, comparison also with testes and testes part, ovary part and testes part
identifying genes of interest based on primarily chromosomal rearrangements
CYP17A1 and FGF9 enhancer fusion androgen production grip strength gonad masculinization meiosis TAD changes
B) Volcano plo
moving FGF9 away from where meiosis is happening
(A) Strategy used to identify genes withaltered 3D chromatin organization as aresult of species-specific rearrangements.
Hypothesis: Scientists predicted that rearrangements in 3D chromatin organization can alter regulatory domains and affect gene expression. Methods: In genome comparisons, synteny breaks can identify rearrangements. Mole genomes were compared with full-chromosome assemblies from human, mouse, and shrew. These were used for comparison as they are the closest taxonomical outgroup with normal ovarian development. These comparisons were performed to identify rearrangements specific to moles. Moreover, Hi-C domain predictions were used to identify genes located in topologically associating domains (TAD) that were affected by a synteny break. They then filtered the located genes according to Gene Ontology (GO terms). Results: They found 286 synteny breaks, and 2,595 genes with altered 3D chromatin organization. Conclusion: After filtering candidates based on GO terms, the list was restricted to 39 genes that were possibly effected. Concept from Ainsworth 2015: A made a connection between female mole's genitalia and the DSD called, congenital adrenal hyperplasia, which causes the body to produce excessive amounts of male sex hormones. If you have this condition and are XX, you are born with an enlarged clitoris and fused labia that resemble a scrotum. In the study they compared the mole genome with humans, so I find this interesting. Concept from Ridnik 2021: In this paper, TAD's are described in a bit more detail, as well as the Hi-C domain. Hi-C is a genome-wide chromosome conformation capture technique. Investigation of Hi-C interaction maps reveled that genome is further organized into megabase-scale units. These are called TADs. TADs there are regulatory elements (enhancers) and they are predicted to interact with their promoters by forming a loop to control gene expression. In the Real paper, they use both Hi-C and TAD predictions for their 3D chromatin organization.
Fig. 1D
can identify potential markers, between tissues
caf-folded using Hi-C data
what order are the contigs within the chromosome, call scaffolds when put them together, get organizational structure for it.
more transcripts than genes because of alternative splicing
Genome assembly
building a genome sequence so can also look at regulatory regions
tissue
showing a Hi-C concept map
intersexuality
word choice, does this work?
adaptive hormone functions hormonal changes that are helping them adapt
B) Strategy used to assign regulatoryelements to candidate genes. Number ofactive enhancers is correlated to geneexpression levels for each tissue
question: Where are footprints of altered gene regulation that might be the consequence of mole specific rearrangements? methods: used the functional datasets that they used in figure 2A. They also used the TAD predictions and rearranged them to delimit a possible region of new interactions for each candidate gene (identified in 2A), and figure out the number of active regulatory elements. results: 17 genes were predicted to gain de novo interaction with regions containing active enhancers. Also there is a correlation between the number of active enhancers and the gene expression levels for each tissue. conclusion: This data helped the scientists draw their conclusion that there is a positive correlation between active enhancers and gene expression amongst 10 genes. For further experiment, they selected the androgen-related gene CYP17A1 and the pro-testicular growth factor gene FGF9. These were selected because they displayed higher expression. Concept from Ainsworth 2015: There have been 25 genes identified that are involved in differences or disorders of sex development. Also, in the past few years, next-generation DNA sequencing has uncovered a wide range of variations in these genes that may cause mild effects of sex differences on individuals but not cause DSDs. This helps point to how sex is a spectrum, something that is seen and studied in moles. Concept from Ridnik 2021: Past studies also looked at rearranged TAD. Looking at gene regulation of the X-inactivation centre (Xic) locus, the importance of TAD partitioning and structures in regulating proper gene expression during development was demonstrated.
androgen synthesis
transport of cholesterol in the mitochondria
A positive correla-tion between active enhancers and gene ex-pression was found for 10 genes. Among thetop-ranked candidates, we selected those dis-playing higher expression for subsequent func-tional validation: the androgen-related geneCYP17A1 and the pro-testicular growth fac-tor gene FGF9
greater conclusion from all of figure 2
GO terms
gene ontology enrichment analysis
predicted to gain de novo interactionwith regions containing active enhancers
hypothesis for figure 2B
AD predictions,to delimit a potential region of new interac-tions for each candidate gene and determinethe number of active regulatory elements con-tained within
question for 2B
Using our functional datasets, we thensearched for footprints of altered gene regu-lation that might be the consequence of mole-specific rearrangements
functional datasets described above, methods for how gathered data for figure 2B
To identify mole-specific rearrangements, we compared themole genomes (T. occidentalis and C. cristata)with full-chromosome assemblies from human,mouse, and shrew, as the closest taxonomicaloutgroup with normal ovarian development
purpose of figure 2A
no relevant candidates were found,we searched for changes in 3D chromatinorganization, on the basis of the hypothesisthat rearrangements can alter regulatory do-mains and affect gene expression
hypothesis for why looking into 3D chromatin organization
Our anal-ysis confirms moles as a distinct family in theorder Eulipotyphla, with shrews and hedge-hogs being the most closely related species(15) (supplementary text)
hypothesis?
investigate the molecular origins of moleovotestes,
question/ 1 purpose of the study
nexception to this paradigm occurs in moles(family Talpidae), in which XX-genotypic fe-males have an intersex phenotype in at leasteight species
unlike other mammals in which sex is determined by genetics
Our results highlight how integrative genomicapproaches can reveal the phenotypic impact of noncoding sequence changes
greater impact
non-cod-ing, cis-acting gene regulatory elements and discuss howthey may control transcriptional programmes that underpinsex determination in the context of the 3-dimensional fold-ing of chromatin.
connecting to how real did same thing
Such surgery is contro-versial because it is usually performed on babies, who are too youngto consent, and risks assigning a sex at odds with the child’s ultimategender identity
part of me thinks, that if you are going to say this is controversial, where is the line in deciding a babies gender based on sex if the baby is too young to decide for themselves
uncover the mechanisms
next steps, possible research proposal?
A study in 1996 recorded womenwith fetal cells in their blood as many as 27 yearsafter giving birth13; another found that maternalcells remain in children up to adulthood14. Thistype of work has further blurred the sex divide,because it means that men often carry cells fromtheir mothers, and women who have been preg-nant with a male fetus can carry a smattering ofits discarded cells.
would this change an individual after being pregnant?
A DSD called congenital adrenal hyperplasia(CAH), for example, causes the body to produceexcessive amounts of male sex hormones; XXindividuals with this condition are born withambiguous genitalia (an enlarged clitoris andfused labia that resemble a scrotum).
similar to moles
In 1990,researchers made headlines when they uncovered the identity of thisgene3,4, which they called SRY
crazy that it was only identified in 1990
“I think there’s much greater diversity within male or female,and there is certainly an area of overlap where some people can’t easilydefine themselves within the binary structure,”
kinda weird to give cells male or female
The function of this vascularization is notknown.
possible research proposal
ovigerous cords
vessels, high degree of vascularization, strings of germ cells
ovarian follicle
functional unit of the ovary
endothelial cells, fibroblasts, andblood-derived cells such as macrophages, lymphocytes,plasma cells, monocytes, and mast cells.
other interstitial cell types
these cells secrete a hormone that plays a role in estab-lishing and maintaining the secondary male sex charac-teristics
Leydig cells
Moreover, it is unclearwhether a single factor induces the migration of one ormore precursor cell types that subsequently differentiateinto the different testicular cell populations by direct
possible research proposal
expressed in Sertoli cells, or more accurately thepre-Sertoli cells
Sry expressed ...
rganizing center of the male gonad and or-chestrate the differentiation of all other cell types
sertoli cells function
meso-derm.
middle layer of embryo
The initial phase is characterized by theemergence of the so-called indifferent, bipotential gonad,or genital ridge, which is identical in males and females.
first stage is present in females and males
owever, varia-tions in mammalian sexual differentiation are known toexist, and this needs to be kept in mind when extrapolat-ing from one species to another.
much research on sex determination done with mice
determined by environment during a sensitiveperiod of embryonic development
sex determined by environment
sex is de-termined by genes at conception
sex determined by genes
describessubsequent steps in developmental pathways, dur-ing which the male and female phenotypes are pro-gressively built up, according to the initial decision
sex differentiation
meant to designate thedevelopmental step at which an individual fate isirremediably directed towards either the male orthe female condition
sex determination
a single eggis more costly to produce than a single sperm cell,female fecundity is limited mainly by her ability toproduce eggs, while male reproductive success islimited by the number of females he can insemin-ate.
interesting to think about after reading the sperm and the egg
anisogamy
sexual reproduction by the fusion of dissimilar gametes
haplodiploidy
sex-determination system in which mlaes develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid
separate sexes, biparentalism, parental controlover sex ratios, Mendelian segregation of sex-ratioalleles, random mating in an infinite population,and no environmentally induced sex differencesin fitness
assumptions for Fisherian model on sex ratios
gene capture
evolution via this
sexes’ or ‘genders’
two different definitions tho?
diatoms
unicellular algae
homologous re-combination between non-sister co-linear chro-mosome pairs, maintained as templates
another way to repair
To what extent repair still plays a role in main-taining meiotic sex is a matter of debate
possible research proposal question????
Such damaging changes cannot be repairedin unicellular haploid organisms; if non-lethal, theywill be transmitted to daughter cells and progres-sively accumulate through generations.
caused by reactive oxygen species in environmental stress
Given its early origin in eukaryotes and near-ly universal distribution, it might seem that sexshould provide large and obvious evolutionary ad-vantages. However, it turns out that costs are mucheasier to identify than are benefits
is sex not needed?
so that sex actually halvesthe number of individuals.
procces for dinoflagellates, eukaryote
volutionarilyrelated enzymes
RAD51 and DMC1
diploid
of a cell or nucleus containing two complete sets of chromosomes, one from each parent
haploid
of a cell or nucleus having a single set of unpaired chromosomes
parthenogenesis
reproduction from an ovum without fertilization
the paternal sperm cell that fertilized thematernal ovum contributed an X or a Y chromo-some
how sex is determined
X’ chromosome
Henking observed, reffered to the element as X, McClung postulated this to be a chromosome, responsible for the inheritance of sex
sex to be determined bythe mother’s nutrition during the first three monthsof pregnancy; a poor diet was thought to result inmales, and a better diet in females
theories, you kinda feel like you still hear some of these today
epigenetic theories of sex determinationhave actually prevailed until recently
seems a bit crazy
Aristotle proposed that males are character-ized by an abundance of fire (the superior element),and for this reason are hot and dry, while females,with an abundance of water, are rather cold andwet
interesting how elements are considered here, also see how this idea from the sperm and the egg of power to the male could have formed through these early philosophies
The dispute about theexact nature of spermatozoa was settled in 1841 bythe Swiss embryologist Albert von Kölliker
concluded that spermatozoa were not independent animals but the products of cells in the testis, and that contact with the egg was needed for fertilization