I was looking at the somatic cell cloning of goats.   One of the advantages of the process said was    All offspring produced are female.    Now I'm confused.  How is this the case?  I know that the embryo after electrofusion is injected into a surrogate mother, but I don't understand how the advantage is that they are "all ... female."
121787
As a student of biology when ever I come by artificial cloning, I always find examples of females being cloned - Dolly the sheep, CopyCat, Daisy, etc. The only male I could see was Fibro mouse and a few more. What is the reason behind this? Is the male genome more difficult to be cloned? I am specifically looking for genetic reasons or other complications.
7451
At school, we've been taught that human infants produce rennin/chymosin (which aids in the digestion of milk). More specifically, it is the peptic cells in the stomach which secrete prorennin, the inactive form of rennin (in addition to pepsinogen, the pepsin proenzyme).  User @another'homosapien's answer  also seems to concur with this (excellent answer by the way, I enjoyed reading it).  However  According to Mod. @AliceD's answer  (yet another excellent answer):     ...in humans there is only a chymosin pseudogene present...   Which (probably?) implies that humans (infant or otherwise) do not produce rennin.  I managed to get my hands on the Textbook of Medical Physiology (Guyton and Hall, South-Asian edition), and according to the book (Chapter Gastric secretions, page 406) peptic cells produce a large quantity of pepsinogen. There is, however, no mention of prorennin. I even flipped over to the Appendix at the back to look up "Rennin", but it turns out there is absolutely no mention of rennin in the book.    My questions,   Some sources claim that rennin is produced in human (infants). Is this true? Other sources claim that rennin is not produced in humans ( we have a pseudogene for it though). Is this correct (I mean the "rennin-is-not-produced" bit, not the "pseudogene" bit)? If rennin is produced in humans only during infancy, what stops it from being produced as we mature? (I'm asking this because every source I've seen that claims that rennin is produced in humans, explicitly states that is done so during infancy...which would suggest that rennin is not produced in adults)
118973
Let's get technical here. Have you ever seen Pikachu excrete? What about Charizard? Or Greninja? No! Well, I don't think anyone has. Is that a sign of them not being actual animals? Let's recall the seven vital characteristics for life: .    Movement Respiratory Sensitivity Growth Reproduction Excretion Nutrition   We've seen Pikachu move (obviously), breathe, touch, and eat.  Does Pikachu grow? Does he excrete?  I am missing one thing out here: reproduction. But we all know Pokémon reproduce, if not by normal means.   Throughout the series, we haven't seen Pikachu grow at all, or other Pokémon. Does evolving count?  We've never seen a Pokémon excrete.   Therefore, can we say they are animals?  Let me make it clear that this is only out of interest, and I have not gone basukas!
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A vast majority of humans get at least some grey hair as they age. As far as I know this applies to both genders and all races. Presumably this means that at least some grey haired humans have noticeable reproductive advantage, or maybe they had it in the recent past.  Theoretically, because this feature is so prevalent, there must be a strong evolutionary pressure to keep it. Am I right? If so, what is it?
43450
Following from this question: :  Is there any evidence that human bodies have systemic self-destruction built into their developmental program? I'm not talking about the cell death response, which I know is an important part of growth, development and cancer prevention.  I've read some things about telomere-shortening but don't know if this is a cause or an effect.
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Hello guys I have this problem which has been really bugging me. And it goes as follows:  Using induction, we want to prove that all human beings have the same hair colour. Let       S(n) be the statement that “any group of n human beings has the same hair colour”.  Clearly S(1) is true: in any group of just one, everybody has the same hair colour.  Now assume S(k), that in any group of k everybody has the same hair colour. If we replace any one in the group with someone else, they still make a total of k and hence have the same hair colour. This works for any initial group of people, meaning that any group of k + 1 also has the same hair colour. Therefore S(k + 1) is true.  I cant seem to figure out where the problem lies in this proof. I have tried a few things and I have concluded the base case is correct. But other than that I can't seem to disprove this proof.
82225
Could cancer be in itself a evolutionary process? Maybe in some way could it be a process of variation? Or would this idea be completely without support, if so, why?   I don't mean that each case would lead to evolution, but that within an entire group of organisms, it could lead to case of of individuals developing ways to resist what caused the cancer, maybe in cases of individuals beating the cancer or in cases of successive generations of off spring from individuals with cancer?   Could it be possible that in rare cases it could lead to the development of new organs or specialized cells?
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In this figure out of the two heteroduplexes formed one is considered to be non-recombinant product(left) and the other recombinant product(right). My question is despite the exchange of middle DNA segment why is the right heteroduplex considered a non-recombinant product or patch. I've been reading two books:    By Nancy Lynn Craig, Rachel Green, Orna Cohen-Fix, Carol Greider, Gisela Storz, Cynthia   By Burton E. Tropp   both had the same illustration and descrpition.
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The problem I've always had with evolution is the actual lack of variation between animals. More specifically, the lack of observable gradual change between species.  Take for example the hammerhead shark. It obviously has a strong connection with a normal shark, but where's the "half-hammerhead" shark? Where's the species that only has a SLIGHTLY wider head?  I really doubt that a single mutation on a normal shark resulted in a head shaped like that, it had to happen gradually. Right? As far as I understand, evolution works by random mutation in a child being somehow slightly beneficial to that animal so it get's to live longer and reproduce more, eventually resulting in it's genetic material in dominating the inferior ones before it. But if it was for whatever reason beneficial to have a slightly wider head, why don't all the sharks have slightly wider heads now? On the other hand, if it wasn't beneficial, how come the hammerhead still exists?  Furthermore, I feel like some characteristics of a certain animal can't really have gradual benefits. There's a lizard that shoots blood out of it's eyes. The original ancestor certainly didn't, and I'm sure that if it's child only bled slightly from it's eyes it wouldn't really help if much in life. So for it to actually become beneficial, it seems to me that there had to be a ton of lizards that had a disadvantage of bleeding slightly. In fact, there had to be so many that they evolved even further in the same direction and kept doing that until they bled so much it's an actual benefit (sorry for this turning so gross). So why did the inbetweeners survive long enough to evolve even more, and why did they THEN die out?
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Scientists have found mammoth blood, and are planning to   How does one go from having its blood to a full blown living mammoth? Is it possible?    Why does it matter if the blood is frozen or not? Suppose one found dinosaur blood, could one clone a dinsosaur (as in say 'Jurassic Park')?
41689
So I planted some berries at that farm just before the bridge with Snorlax on it, in the hope of expanding my supply. I watered them, came back the next day and each tree had sprouted nicely. However, some of them had an oddly-coloured berry, which (upon picking) I found out was a berry of an entirely different type altogether.  Some scientist then came up to me, and told me she was 'researching berry mutations' and that I should tell her what mutations I find.  My mutation was a Qualot Berry, which (according to the scientist) was made from Oran and Pecha Berries. But how did this happen?  Is it something to do with the way the bushes are planted next to each other, or in a line? Or Is it completely random?  Further to this, What other Berry Mutations can I find?
31613
In a country where everyone wants a boy, each family continues having babies till they have a boy. After some time, what is the proportion of boys to girls in the country? (Assuming probability of having a boy or a girl is the same)
4571
Background I am a computer programmer who is fascinated by artificial intelligence and artificial neural networks, and I am becoming more curious about how biological neural networks work. Context &amp; what I think I understand In digesting all I have been reading, I am beginning to understand that there are layers to neural networks.  A front-line layer of neurons may receive, for example, a visual stimulus such as a bright light.  That stimulus is taken in by the front-line neurons, each of which produce a weighted electro-chemical response that results in a binary decision to pass an electrical charge through its axon to the dendrites of the tens of thousands of neurons to which it is connected. This process repeats through layers channeling the electrical signals and focusing them based on their permutations until ultimately a charge is passed to a focused response mechanism such as the nerves that control shrinking of the pupils. Hopefully I got that correct. Preamble to the question ;) Assuming that I am not completely off-base with my basic understanding of how a biological neural network operates, I am beginning to grasp how an input (stimulus) results in an output (response) such as motor movement or reflexes.  That would just seem to be basic electricity of open and closed circuits. HOWEVER, what confuzzles me still is how a memory is stored.  The analogy to an electrical circuit breaks down here, for in a circuit I can't really stop the flow of electrons unless I dam up said electrons in a capacitor.  If I do that, once the electrons are released (accessed), they are gone forever whereas a memory endures. So. . . How the heck are memories constructed and stored in the human brain?  Are they stored in a specific region?  If so, where?
113457
If a hermaphrodite animal (like slug, snail, etc) finds a partner they can mate immediately.  If another animal with "normal" reproduction (lets say a mouse) finds a partner they can only mate if they are opposite genders.  So it seems logical that the hermaphrodite way of reproduction is more successful than the "normal" way.  But it is not, as far as I know all higher developed species are using, the standard way of reproduction (male and female).  Why? What are the disadvantages of hermaphroditism?
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This question is brought on by a Sci Fi novel I am thinking about writing. The plot device involves a colonist in charge of building a population on a new planet who loses his supply of embryos and so forth in the landing. With the artificial "wombs" intact, he populates the planet with clones of himself.  If he wanted to introduce enough variation (without making up new genes, only rearranging) in the population to allow them to be able to reproduce naturally without inbreeding problems, would he be able to? In particular, could he make a woman?  Alternately, could a woman (without a Y chromosome) do the the inverse?  At the risk of introducing bias into the answers, the plot as it stands assumes he is a male and he CAN'T do any of the above and he is restricted to clones.
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Version 1.0 of Minecraft added baby animals and breeding.  So now I've begun animal husbandry, and I'm off to a good start, I'm just growing impatient with a few of them.  Specifically, they won't grow up.  How long will it take my calves, chicks, and piglets to grow up into fully -able cows, chickens and pigs?  On a related note, how long do I have to wait after breeding a pair of animals before I can breed them again?
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Today I read a  about how Pablo Escobar had once imported 4 hippos (1 male, 3 female) into his estate in Colombia for his private zoo. After his downfall, while other species were shipped out, hippos were considered too big to move and expected to not survive. However, to the surprise of all the hippos are thriving and are so numerous that there have been calls to cull them. From the report:  Numbers are projected to only get bigger. [Colombian biologist Nataly] Castelblanco and her peers say the population will reach over 1,400 specimens as early as 2034 without a cull - all of them descended from the original group of a male and three females. In the study, they envisaged an ideal scenario in which 30 animals need to be culled or castrated every year to stop that happening.  My understanding is that since there was only 1 male, the gene pool would be limited and lead to lot of inbreeding in the descendants. This would cause population to not explode because some individuals would be unfit to survive. Why has this not happened in case of hippos? Is it because there are 3 females (probably unrelated to each other) which keeps gene pool large enough? Or can mutations explain this phenomenon? Would results have been different if originally 2 females had been moved and only 1 retained? EDIT - I have just found that  is maybe less than 100 individuals which though big is not massive. EDIT2 - I have edited the question title to keep focus on the hippos although a general answer would be welcome.