7

I can only offer a partial answer on the theoretical aspects. I don't know if you are familiar with the mid-90s papers by Otto et al. (Otto & Goldstein,1992, Otto & Marks, 1996), but these are definately relevant to your question. They deal with the "masking hypothesis" of diploidy, i.e. that deleterious mutations can be masked by "healthy" alleles, ...


5

First of all I am not sure if your examples are per se correct. But they might also be an additional bonus. Secondly, I would like to refer to two articles: "Polyploidy" and "The advantages and disadvantages of being polyploid". One of the main benefits could be allowing organisms long-term evolutionary flexibility. Often adapted polyploids can undergo a ...


4

Yes, D. Attenborough probably refers to ploidy number Ploidy number Humans for example are 2N (except during the spermatozoid and ovule phase of human existence) meaning that they carry two copies of each autosome (=non-sexual chromosomes). Some species are 1N (haploid), some are 3N (triploid), etc… It would actually be more correct to talk about the time ...


3

Dominance works in the same way. However, polyploids have complex inheritance patterns! 1. Punnett square for polyploid inheritance One might assume that you would need a four-dimensional table for tetraploids, a six-dimensional table for hexaploids, and an eight-dimensional table for octoploids. The table you mentioned in this case should be the ...


3

This is not on theoretical grounds, but here is an existence proof: a number of bacteria, which reproduce asexually, are polyploid. Here is a blog I really like informally discussing the concept of ploidy in bacteria. The example I am familiar with is cyanobacteria, which can have 3-4 all the way up to 142 copies of its genome, according to this paper (1). ...


3

I haven't seen this particular film, but other documentaries by Dr. Attenborough are very accurate and well done. In contrast to Remi.b, I'm pretty sure Attenborough referred to the ancient whole genome duplication event in land plants recently discovered in angiosperm genomes by the presence of multiple paralogous genes. The scenario is that at a certain ...


2

Ploidy and reproductive isolation in plants Speaking generally, there is simply no question that for flowering plants there can be a sexual pathway between diploid and polyploidy levels. The question is how wide is the bridge and how much flow is there in either direction. In other words the questions become "How much flow?", "How meaningful the flow?", "...


2

The short answer appears to be "no". The longer answer seems to be dependent on what you mean by "viable". Triploid humans do exist that apparently arise from dispermy, but most such fetuses die shortly after birth. Those that do not die soon after birth have a variety of health issues such as intellectual disability; "The few [triploid] infants that do ...


2

Note that it is customary to restrict posts to a single question, which is easier to answer for these complex topics. I'll do what I can here. I'm going to deal with everything at once and then reference pieces in direct reference to your 3 questions. MECHANISMS OF CONSTRAINTS ON PLOIDY I think that it's worth separating out some of the different ...


2

Ploidy number vs number of alleles You seem to be confounding number of alleles with ploidy numbers. You rightly figured the number of possible genotypes for a diploid individuals when there are 3 possible allelic states. When you ask for a pentaploid, are you many alleles are you wiling to consider? Pentaploids are very rare If I am not mistaken, ...


2

There is no single answer for a gene. The most correct thing to do is to use a set of genes across many locus and measure the correlation of copy number across them first, and only use the ones which co-segregate as single copy number as the measure of 'one copy'. This is the same approach used for qPCR and is the basis of the widely used geNorm algorithm (...


2

The following is probably a good set, it's for Arabidopsis you need to check if it fits with your need. CBP20 Gene Gene Locus: At5g44200 Actin-2 Gene Gene Locus: At3g18780 UBC Gene Gene Locus: At5g25760 SIGMA sells primers set for these: http://www.sigmaaldrich.com/life-science/molecular-biology/plant-biotechnology/plant-molecular-biology/control-primers-...


2

Just flying from the waist: filter approach: If there is a data source that has the expression data for cells in multiple tissues for any organism i would use that to find the housekeeping genes by sorting which genes are expressed in the greatest number of cells (think excel or XML). Next, I would check which of those genes are also found in/similar to the ...


1

In short, being haploid or polyploid should not protect you from Selfish Genetic Elements (SGES). Almost all eukaryotes are polyploid. Plants are the oft-cited example. Wheat, I believe, is hexaploid for example. Polyploid bacteria are the exceptions typically (if we consider ploidy to be of the whole genome). However, even in truly haploid bacteria, the ...


1

Yes, it is possible. There seems however to always come up with a cost in fertility eventually of the order of 2/3! You should have a look at Ramsey and Schemske 1998. I don't remember it well enough to make a good summary (maybe someone else could do that?!) but it is a classical article. Here is a sentence from their abstract In contrast to the common ...


1

In the genus Rhododendron polyploid species are common especially in deciduous azaleas and lepidotes. Yet complete reproductive isolation of the poylpoid species from the closely related diploid species is the exception rather than the rule. Closely related diploid and tetraploid species interact in natural contact zones to create triploids and some ...


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