Wikipedia:Reference desk/Archives/Science/2017 June 30
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June 30
editUnfertilized ovary and ripened ovary in angiosperms
editWhat is the difference between a womb and an ovary? Can an ovary transform into a womb if it is fertilized and bears seeds? If sperm means seed, then what is a seed inside a sweet fruit? Maybe angiosperms have two kinds of seeds? 2600:387:0:80F:0:0:0:83 (talk) 12:58, 30 June 2017 (UTC)
- Maybe the "seed" is really the offspring. But the sperm is the true seed? 2600:387:0:80F:0:0:0:83 (talk) 13:52, 30 June 2017 (UTC)
- Angiosperms are flowering plants - they do not have wombs or produce sperm. The female part of a flower called an ovary, containing the ovules in which the female egg cells are produced. The male part of a flower is the stamen, which produces pollen. When the egg call is fertilised by pollen, the ovule develops into a seed, while the ovary becomes the fruit which contains the seeds. That is the basic pattern - though there are many variations - see Plant reproductive morphology. Wymspen (talk) 18:00, 30 June 2017 (UTC)
Rh factor in other animals
editApart from humans and macaques, does rhesus factor exist in other animals too? Our article doesn't clarify that. Also, interesting know which species evolved it first (maybe monkeys, maybe not). --212.180.235.46 (talk) 14:20, 30 June 2017 (UTC)
- The Rh blood group system is actually very complicated having 50 distinct defined antigens in humans. In common parlance, Rh+ often means only the presence of Rh antigen D. The D antigen only has close analogs in gorillas and chimpanzees but the representatives of the broader family of Rh proteins can be found in essentially all animals. [1] Dragons flight (talk) 16:01, 30 June 2017 (UTC)
- All animals generally means all parts of the kingdom Animalia Nil Einne (talk) 03:35, 1 July 2017 (UTC)
- This fact is amazing, if it's true (did Dragons flight mean alike ?), since it means that the corresponding part of the genome is extremely preserved in evolution. In other, more practical words, it's highly & fundamentally crucial to survival. בנצי (talk) 08:47, 1 July 2017 (UTC)
- Not necessarily. It just has to not be harmful. Since blood transfusions don't happen in nature, and the placental barrier (and similar barriers in non-placental mammals and other animals) protects offspring of other blood types, it doesn't seem to be very dangerous to have different blood types. Therefore, natural variation produces many varieties. StuRat (talk) 13:35, 1 July 2017 (UTC)
- Didn't either of you at least glance at the source? It says RHAG homologs are found in non-erythroid tissues, which shouldn't be surprising since not all animals have circulatory systems or erythroid cells. It does appear there is some not yet well understood (at least per that source which was last update in 2005 so possibly not very reliable on this) functionally related selective pressure. Again this makes sense since in the absence of a selective pressure, random chance would suggest they would have been lost in at least some lineages. RH orthologs and paralogs are also found in slime mold further supporting this idea. (So actually it probably goes beyond animals.) Nil Einne (talk) 16:25, 1 July 2017 (UTC)
- You can see some of the homologues by looking at HomoloGene link in the article. The protein is basically a big ammonium transporter domain, though some other functions are noted in the MGI data. (Causing blood transfusion incompatibility is not actually a function, just something people discovered when they started fooling with Mother Nature!) Functionally MGI (I think) mentions that red blood cell ghosts (the membranes, in other words) don't transport ammonia as well in knockouts. There is an Rh deficiency syndrome associated with RHAG or RH mutants [2]. I suspect, but did not check, that the cell fragility has to do with the hindrance to transporting ammonium ions. Since ammonium is a basic nitrogenous waste its transport is a universal issue of animals. (Plants have an opposite reason to transport it) Wnt (talk) 11:34, 2 July 2017 (UTC)
- Thanks. Ammonium transporter was mentioned in the other source although I didn't explore it very well. As you said, blood transfusion incompability is an irrelevant "bug" in nearly all circumstance so isn't likely to result in a selective pressure although Rh disease probably could do so. (So that part of StuRat's answer was mostly correct.) But there's clearly some positive selection pressure which preserved and expanded the range of Rh proteins. Nil Einne (talk) 13:51, 2 July 2017 (UTC)
- You can see some of the homologues by looking at HomoloGene link in the article. The protein is basically a big ammonium transporter domain, though some other functions are noted in the MGI data. (Causing blood transfusion incompatibility is not actually a function, just something people discovered when they started fooling with Mother Nature!) Functionally MGI (I think) mentions that red blood cell ghosts (the membranes, in other words) don't transport ammonia as well in knockouts. There is an Rh deficiency syndrome associated with RHAG or RH mutants [2]. I suspect, but did not check, that the cell fragility has to do with the hindrance to transporting ammonium ions. Since ammonium is a basic nitrogenous waste its transport is a universal issue of animals. (Plants have an opposite reason to transport it) Wnt (talk) 11:34, 2 July 2017 (UTC)
- Didn't either of you at least glance at the source? It says RHAG homologs are found in non-erythroid tissues, which shouldn't be surprising since not all animals have circulatory systems or erythroid cells. It does appear there is some not yet well understood (at least per that source which was last update in 2005 so possibly not very reliable on this) functionally related selective pressure. Again this makes sense since in the absence of a selective pressure, random chance would suggest they would have been lost in at least some lineages. RH orthologs and paralogs are also found in slime mold further supporting this idea. (So actually it probably goes beyond animals.) Nil Einne (talk) 16:25, 1 July 2017 (UTC)