Why There Are Two Sexes

I have no degree in Biology, but I would like to present the hypothesis about the two sexes emergence. I started working on this idea many years ago, but didn’t finish it, partially because I didn’t have much of opportunity to discuss it with experts. I sent it a couple of times to scientists, who in my opinion could’ve been interested, but the idea didn’t generate much of enthusiasm. The most comprehensive respond I received was as follows:“ . There is a large amount of data that indicate that a process like what you describe is not happening in biological systems that are studied presently. Nobody would have necessarily stated that their data rule out a mechanism similar to what you propose because they wouldn't think about this possible mechanism.”I would like to have a more specific objection to my hypothesis. Can someone point to these evidences? Or maybe someone knows the data that are in favor to this hypothesis and even could propose the experiment to falsify or to confirm this hypothesis. Any contribution will be greatly appreciated.P.S.
Sorry for my grammatical and stylistical mistakes. Unfortunately, my 15 years old editor-in-chief is too busy with her own homework. Please let me know if something I am writing is unclear and needs corrections.Thank you,
Mark Iosim_________________________WHY THERE ARE TWO SEXES EXIST?_________________________STRUGGLING WITH EXISTING PARADIGM
Years ago, I was curios about very general aspects of living systems development and even started my own investigation. Step by step the scope of my investigation was narrowing down and eventually it led me to a very controversial hypothesis about DNA molecule genetic activity that however may explain two sex’s existence.The double strand DNA molecule contains one DNA strand inherited from the parental DNA strand and one newly synthesized. Both strands carry genetic information, however, according to my hypothesis, only one of them - newly synthesized strand is genetically active in the double stranded DNA molecule, while another strand is blocked from transcription. As a result, sister DNA molecules, emerging as result of single DNA autoreplication, while having identical genetic code, should have a dramatic difference in their genetic expression, because they have different newly synthesized DNA strands. Another word, according to this hypothesis, DNA autoreplication process always yields two sisters DNA molecules (and sister cells accordingly) of opposite complement types.Unfortunately this hypothesis contradicts to one essential paradigm of molecular biology stating that in the most cases, sister DNA molecules must have identical genetic activity. Though, I could not understand how that paradigm was tested, i.e. how the genetic activity of single DNA molecules was determined. Even modern methods, are often unable to determine a single DNA molecule genetic activity. Instead, the cumulative genetic activity pattern of "DNA soup", consisting at least of thousands or even millions DNA molecules, is only tested. Despite a thorough literary search and discussions with experts in the field, I came upon an unexpected result: nobody could uncover any proofs for this paradigm, regardless of a general confidence in their existence.THIS HYPOTHESYS IS DEAD ON ARRIVAL.
I have continued developing my controversial idea that seems to contradict not just a paradigm, but a common sense also, because our hypothetical cells have a limited access to its own genetic information. Yet, I may argue that a cell doesn't need genetic information itself, but the products of that information only. This is like a cake. You do not need to know the recipe to enjoy it. Genetic information serves as a recipe for cell products. If a cell has enough of them, it should not worry about the genetic recipe. For instance, our blood cells do not contain genetic information (nuclear DNA), but the necessary products only and the cells successfully maintain their living standards.Regardless the limited access to some genetic recipes our hypothetical cells should have complete set of necessary genetic products, because cells may inherit them from a parental cell. The “pregnant” parental cell holds inside its boundary two sister cells that emerge as a result of DNA autoreplication process. The sister cells “cook” different (complement) dishes, but able freely share them while being inside the same boundary of a parental cell. These products, inherited by sister cells after separation, must provide them not only with a vital capacity, but also make them practically indistinguishable.When parental ingredients become consumed, to survive our hypothetical cells have no choice, but auto-replicate again to refill missing genetic products. So, our hypothetical cells propagate, not because they are "worry" about future generations and survival of species, but because cells “worry” about they own vital capacity. Dependence of this cell on propagation must have forced their breeding that eventually, should cause the predominant spreading of these cells (compared to the cells, whose survival doesn't depend on autoreplication). Therefore, "our" cells may have been the main materials for evolutionary steps that followed i.e. they must have been the brick, which had been laid in foundation of the living Nature of our planet.EMERGENCE OF TWO SEXES
It is well known that under conditions of low temperature or starvation, the cells cannot grow and auto-replicate themselves. Under this condition, our hypothetical cells must die after parental product’s depletion. This is not a speculation only. There are numerous observations (but no explanation) of massive cell deaths occurring during a long artificial block of cell auto-reproduction. To survive in this circumstance, the cells of opposite type can merge with each other and the resulting cell can generate a complete set of necessary genetic products and this way is capable of survival.
There is a striking similarity between the cells of our model and well-studied single-cell eukaryotic organisms. In their populations, each cell produces two sister cells of opposite type and as a result, the population consists of two type of cells. Under conditions preventing cell growth and auto-replication, the cells of opposite types merge to start the most ancient rituals, referred as the sexual process.Based on this and other facts I came to a conclusion that sexual process emerged as a survival mechanism during unfavorable environmental conditions. In the beginning, cell merging was divorced from reproduction that emerged later. Eventually cell-merging process led to recombination of genetic material. During evolutionary stages that followed, recombination proved its advantage and has become more regular in character. However, even now we can often observe cell couples, who neglect their roles. These couples go through conjugation, but like a reminder of past times, they do not mix their genetic material and don't form a family (zygote).In this post I covered a basic mechanism that may explain emergence of two sexes. This model may explain some other aspects of two sexes existence you can read about in my essay "WHY THERE ARE TWO SEXES EXIST?" home.earthlink.net/~miosim/.../why_there_are_two_sexes_essay.pdfThe most complete form of this hypothesis is "DNA Asymmetric Gene Activity”
http://home.earthlink.net/~miosim/.../dna_asymmetric_gene_activity.pdfEdited by Adminnemooseus, : Changed topic title from "WHY THERE ARE TWO SEXES EXIST?" to "Why There Are Two Sexes". Could also have been "Why Two Sexes Exist". One way or the other, I'm getting rid of all those upper case letters (maybe I could sell them to Arachnophilia?).Edited by miosim, : No reason given.Edited by Adminnemooseus, : Shortened display form of two URL's, to restore page width to normal.

molbiogirl,Can you please collaborate on this, even it would spoil fun for RUSD.

molbiogirl,Indeed I didn’t have Intro Genetics and therefore I am trying to use any opportunity to fill the gaps. I thought you are referring to a weird cases where more than one cell merge together for reproduction. But I do not want to go into this area, especially if it isn’t what you meant.The phenomenon you described belongs to sex determination mechanism that actually depends not only on X or Y chromosomes, but on autosomes abnormality also. I briefly mentioned this phenomenon in my essay as follow:“ . According to the chromosome theory an infant’s sex is definitely determined by a distinct sex-chromosome pair when the women’s X-chromosome joins with the man’s X- or Y-chromosomes. Depending on the combination XX or XY, parents will joy a girl or a boy. This theory has been proved by a good deal of fact, but there are number of examples, which are exceptions of this rule. For instance, the genetic factors of sex in plants often depend upon surrounding conditions and in some animals (for example media Crenomytilus grayanus dunker) depends on age. Experiments on fruit flies revealed that not only sex chromosomes, but also other chromosomes could determine sex, independently from the zygote’s sexual constitution. Another very important factor for sexual differentiation are hormones. By injecting female hormone into a chicken embryo, it is forced to become a female, even by its chromosomal constitution it was destined to become a male. When it hatches, this artificial female cannot be distinguished from an ordinary, "normal" female.
In the beginning of 20th century, the idea of organism bio-potentiality was formulated. According to this idea, an organism has inclinations for both, male and female sexes, and determination of sex occurs during development. For example, in the beginning stages of embryo development, human gonads of both sexes are non-distinguishable. Such gonads contain two main structures - cortex and medulla. During development of male embryos, the cortex degenerates, and the medulla forms a testicle. In female embryos, a medulla degenerates, and the cortex forms an ovary.Based on the idea of bio-potentiality and employing our model, we can build a speculate scenario of the organism sex development. The main roles are cast between "patriarchal" and "matriarchal" cells that determine male and female properties of an organism ..............”molbiogirl: The main concept is not as sexy, as it appears from the title of this thread. It isn't about sex in humans, it is rather about sex in microbes. Actually the main mechanism I am proposing in my hypothesis is the cell differentiation mechanism, in which sex is just only one specific case of this differentiation. Of cause, I tried to extend this hypothesis into development of human sex also, but it isn’t in my OP. My OP is intended just to comply with the requirement for OP to be short and specific. For actual discussion, I expect, that at least the essay
http://home.earthlink.net/~miosim/sitebuildercontent/... will be read.For reader having background in Biology or who interested in Molecular Biology I would recommend to read the more formal version of this hypothesis.
http://home.earthlink.net/~miosim/sitebuildercontent/...___________________________________________________________________RASD, having fun yet?I did some homework and look over your essay “Sexual Selection, Stasis, Run-away Selection, Dimorphism and Human Evolution”. This is outside of my interests, but you may be interested to read about research of Vigen Geodakyan
Vigen Geodakyan
He developed a very elegant theory about distribution of evolutionary roles: for a male to "design and test" of new varieties and for a female, to “save the best”.Have a fun.Edited by miosim, : No reason given.Edited by Adminnemooseus, : Shortened display form of two (same?) URL's, to restore page width to normal.

RAZD,I am not knowledgeable in the field of population genetics to judge correctness of Vigen Geodakyan’s theories.More than 25 years ago, I first read the popular article (brilliantly written, but unfortunately not translated to Enflish)
SHE and HE
and later following few of Geodakyan’s scientific publications, I was impressed with the clarity of his thinking, elegance, simplicity a boldness of his prediction.One example of his idea from onother popular magazine
WHY TWO SEXES?“ . A good sculptor, before making a sculpture out of marble, will create many models out of clay. Nature acts similarly. Like a sculptor, nature first creates a large variety of males (clay models), testing them and selecting good variants to implement later in females (marble sculpture). Thus, in a population, new qualities first appear among the males and may afterward appear among the females . ”
. Thus, if the male and the female are distinct from each other in some quality, say in the height or color, one may predict the direction of change; namely, the quality is changing in the direction from the female to the male. For example, if males are bigger than the females, then there is an evolutionary tendency for size to increase in the species. In the other case, if males are smaller than females, the species evolves to have smaller specimens.
We may conjecture that humans are becoming taller at this stage of history, because an average man is taller than an average woman (Fig. 5). Among the spiders, the tendency must be opposite, because their males are smaller than the females. The anthropologists and entomologists believe this is the case: mankind is growing . “Based on his theory Vigen Geodakyan’s predicted the distribution of the gender related diseases that, as I understood, were conformed later by other authors.Bur again, I never followed closely this sorts of research, because I was interested in the most general aspects of biological system development only and was just temporarily diverted from my main subject. Also I am opposing indiscriminate use of methodology of Supreme Purpose that Vigen Geodakyan’s employed at full extend. Yes, they are the same links as in the PO (just reminder, PO itself not the same as an essay). Depending of the preferred level of discussion, you may want to read the essay “Why There Are Two Sexes” or more expended and formal its version “DNA asymmetric gene activity”. My theoretical model also expects that in some circumstances, more that two sexes may exist (more than one cell merging process, but didn't try to find them, but keep focus on the most typical cases. Can you present your examples? I do not know if you can follow the sexual development described in my hypothesis without understanding the proposed mechanism of cell differentiation?Edited by miosim, : No reason given.Edited by AdminModulous, : fixed urlsEdited by miosim, : No reason given.

Sorry RASD,I thought it is readable enough, but any way, I am repeating the portion that relates to the links.More than 25 years ago, I first read the popular article (brilliantly written, but unfortunately not translated to English) SHE and HE and later following few of Geodakyan’s scientific publications, I was impressed with the clarity of his thinking, elegance, simplicity and the boldness of his predictions. One example of his idea from another popular article
WHY TWO SEXES?To view these links you need MS word. I hope, you do not have problem with that.Edited by miosim, : No reason given.Edited by miosim, : No reason given.

Is it still problem with the link? It could be that your request and my action happened in the same time.

RASD,So, the quote below (even this is a middle school level biology) struck you ... ...because you think ... ... even mutations have no relevance to above quote.And then you reject this: Because of quote from Wickipedia: while the complete quote is: I am confused, probably because I do not have the solid foundation in Biology. If you found that Geodakyan’s theory is false, it is fine with me. I have no intention to study Geodakyan’s theories in detailes to defend him.Now I’m looking forward to hear your criticism about my hypothesis.Edited by miosim, : No reason given.

molbiogirl,Thank you for this crush course.

molbiogirl,
I do not see contradiction between me and you. Can you please clarify.

molbiogirl,Did you see Fig.1 on DNA Asymmetric Gene Activity... where only one DNA molecule (say a single chromosome) is shown? Each of shown genes (three total) is unique.

To avoid confusion lets use a simplest scenario: a single diploid cell having one chromosome in its haploid set. Each chromosome, according to model, is of one possible type: matriarchal or patriarchal (see mechanism of cell differentiatiation, page 6). According to model, the distribution of parental chromosomes to daughter cells may lead to any of the following scenarios:
1. Only one allele of particular gene is expressed. (if both chromosomes are of opposite type).
2. Both alleles are expressed. (if both chromosome are of the same type and this particular allele are on the active DNA strands).
3. Both alleles are blocked. (if both chromosome are of the same type but this alleles are on the blocked DNA strands).Edited by miosim, : No reason given.

I do.
I don't worry that model allows condition 3 (person would not have a blood type!) as long as model doesn't require this condition. Actually Condition 3 should play a crucial role in the cell differentiation mechanism. Thanks to this condition A/B genes are blocked completely in the non blood cells, neuron for exampleEdited by miosim, : No reason given.Edited by miosim, : No reason given.

One of the problems in our communication is that you are focusing on organism and I am focusing on individual cells. Lets keep it simple and finish with individual cell first. So, for individual cell the complete blockage of A/B genes or even 50% of all genes not a problem, but mechanism by with cell differentiation occurs.For blood cells, both A and B alleles must be engaged, so according to my model, blood cells allays have the same type of appropriate chromosomes with A and B alleles located on the active DNA strands.Edited by miosim, : No reason given.

Agree.But my model also predicts a possibility that some cell may receive incorrect set of chromosome type (I mean patriarchal and matriarchal types) that would probably will cause cell death. But this is abnormalities. Normally blood cell receives the correct type of chromosome, so AB phenotype is properly expressed. How cells maintain the correct distribution of patriarchal and matriarchal types of chromosome during cell division, I speculate on page 9 (linkages). But this just a general model that not intended to explain all intricate details of cell differentiation.

One more comments.Normally blood cell receives the correct type of chromosome, so AB phenotype is properly expressed, but during cell proliferation only one daughter cell will properly expressed AB phenotype while another will have blood type phenotype completely suppressed. This cells I called “inverted” type. they cannot differentiated (see page 7), but produce the correct cell only (by dividing). Existence of these “inverted” cell is the fundamental properties of the differentiation process described by this model.