11
votes
0answers
173 views

What is the percentage of people living in England in 1500 AD whose lineage is still alive?

This sounds a bit random but it stems from a lecture in statistical genetics which I attended a while ago. We were shown a population lineage graph from which it was clear that most lineages go ...
11
votes
0answers
89 views

What have the L-systems (Lindenmayer systems) been actually used for in biology?

Wikipedia: An L-system or Lindenmayer system is a parallel rewriting system and a type of formal grammar. L-systems were introduced and developed in 1968 by Aristid Lindenmayer, a Hungarian ...
8
votes
0answers
98 views

Understanding the brain: how are neurotransmitters released in the brain?

I have a basic knowledge of how neural networks work. A potential difference is created that forces sodium, potassium, chloride, and calcium ions to flow which carries an electrical signal to the end ...
8
votes
0answers
145 views

Why do bananas go brown quicker in the fridge?

Perhaps the title should be: Why do specifically bananas go brown quickly when left in the fridge? Bananas go brown over time because of the oxidation of phenol residues. Bananas go brown quicker ...
8
votes
0answers
103 views

Selection for less efficient egg transfer in Human Botfly life cycle

I have heard that the Human Botfly transfers its eggs through other invertebrates [1], and it strikes my curiosity that if an insect could simply land on its host directly to deposit its eggs, then ...
8
votes
0answers
93 views

How to define “Quasifixation” in continuous approximation of finite population?

Background Many models including the famous very first models derived by Sir Ronald Fisher in his early career, assume infinite population size. In an infinite population, an allele can rise in ...
8
votes
0answers
147 views

At which step apply a detection filter when preprocessing microarray data? (Before/After normalization, batch effects removal)

I am trying to understand what is the best practice when preprocessing microarray data using a detection filter (on scanner p-value). Suppose I have a microarray dataset that I have to normalize with ...
7
votes
0answers
59 views

Standard practice for generating rarefaction curves from Next Generation Sequencing data

We have a few million 18S reads from a particular environment. The reads have been clustered into Operational Taxonomic Unit (OTU), and the OTUs annotated against a reference database. To generate a ...
7
votes
0answers
231 views

Contact Inhibition of Cell Division: Signaling Pathway

The following article refers to contact inhibition of cell division in epithelial cells, specifically MDCK cells: Collective and single cell behavior in epithelial contact inhibition. In their review ...
7
votes
0answers
128 views

DNA-DNA cross-linking with formaldehyde?

The 3C (chromosome conformation capture) technology for studying chromatin 3D organization starts by a cross-linking step using formaldehyde to find segments of DNA interacting. In my understanding ...
6
votes
0answers
214 views

What bacteria shed harvestable energy from root zone organic matter?

I recently heard of a successful effort that harvests energy from soil at plants' bases due to apparently bacterial breakdown of wastes from the plants: Via photosynthesis a plant produces organic ...
6
votes
0answers
67 views

Identity by descent among unrelated individuals

I was reading a couple of papers which talk about IBD (Identity by descent) among unrelated individuals (for eg. http://www.pnas.org/content/109/4/1193.long). However they do not seem to clearly ...
6
votes
0answers
114 views

Up to date, extensive documentary about dinosaurs?

I just finished reading the Wikipedia page about dinosaurs, and I very much enjoyed it. I knew that much of what I learned in the 80's as a child is (and was) incorrect, and now that I am a parent, I ...
6
votes
0answers
78 views

Statistical method for characterizing the relationship between body mass and metabolic rate

There is a dataset that contains body mass ($x$) and metabolic rate ($y$) from many different organisms. It is common to fit the data to the model of the form $y=ax^b$ and estimate the parameters $a$ ...
6
votes
0answers
474 views

Evolutionary reasons why you cannot tickle yourself but masturbate

There are obviously good reasons that explain why you cannot tickle yourself (see e.g. here). This got me thinking why it is possible to masturbate... Wouldn't it make more sense to not being able to ...
6
votes
0answers
29 views

Would constant light or fading light be registered as more wakefulness promoting by the Supra Chiasmatic Nucleus?

During the fall and winter season, a number of people are experiencing Seasonal Affective Disorder. One of the way it has traditionally been treated is with a dedicated lightbox - a very high ...
6
votes
0answers
70 views

How to measure Na/K channel activation at the membrane level?

Assume that there are two different signals occurring on the ECG - during depolarization and repolarization in the standard ECG. I was advised not to use the standard ECG in measuring the exact ...
6
votes
0answers
52 views

Effect of Aging on SA node's sympathetic fibers

I am trying to understand the effect of aging on the sympathetic fibers of SA node. I know that aging shifts the vagal curve to left in frequency due to aging. However, I am interested if aging has ...
6
votes
0answers
71 views

Does preservation in ethanol alter leaf litter mass?

I have benthic samples that were collected with an Ekman dredge from some small ponds. The samples contain quite a bit of coarse particulate organic matter (CPOM, basically dead leaves). I would ...
6
votes
0answers
132 views

Comparative cost of RNA-seq vs sequencing full length cDNAs

I am in the process of assembling and annotating the genome of a non-model organism, using almost exclusively short read (paired-end Illumina) data. Throughput is one obvious benefit of these data ...
5
votes
0answers
78 views

Why do I see different hues of colors between each of my eyes?

Frequently, I see colors with a slightly different hue when looking through my eyes individually. The right eye is more red-tinted ('warmer' hued) and the left is typically more blue-tinted ('cooler' ...
5
votes
0answers
36 views

Is high metabolism linked to high evolutionary turnover?

I recently read The Dinosaur Heresies by Robert T. Bakker, a 1986 popular science book presenting arguments for an active lifestyle and high metabolic rate in dinosaurs. One of the arguments that ...
5
votes
0answers
173 views

What are the branches of system ecology?

What are the branches of system ecology that scientists research in nowadays? Or what can system ecology can applied to, or be used? I have read its Wikipedia page, but sadly it doesn't answer my ...
5
votes
0answers
70 views

Help Identifying Tree

I live in the upper southeastern region of Arizona in U.S. There's a type of tree growing in my back yard that I can't seem to identify. Its growing in an arrangement very similar to an ocotillo ...
5
votes
0answers
68 views

Which organism is this?

Place: Bangalore, India Month: September, 2015 Current weather: Cloudy and rainy Google images search was just giving me dragonfly photos. That organism is on grass blade. Image is captured by ...
5
votes
0answers
60 views

How does a garlic clove thrive inside a closed refrigerator?

A garlic clove has been growing very well inside a closed refrigerator. It has developed beautiful green stalks, which I think are the equivalent of leafs. Since they are green, I assume they ...
5
votes
0answers
54 views

Variance in Fst in the infinite island model

The most famous result in the study of structured populations come from Sewall Wright. He showed that in an island model, where each subpopulation is of size $N$ and the migration rate is $m$, then ...
5
votes
0answers
66 views

Is there a mechanism by which mammals lose interest in a partner after mating?

I'm reading the book called "Cupid's poison arrow", which revolves around a rather simple assumption: most mammals, including humans have a genetic program that is responsible for ever increasing ...
5
votes
0answers
92 views

What is basis of multifunctionality of “master glands” in the endocrine system?

I have just started reading about the endocrine system and I am having some difficulty understanding the basis of distribution of glands and associated hormones. I am using multifuntionality to ...
5
votes
0answers
39 views

Is it possible that the vapour form of propylene glycol could lower a humans blood oxygen saturation by the manner in which N2O does?

My understanding is that by inhaling nitrous oxide leads to the body not being able to take in as much oxygen as it usually would. Is it possible that a heavier soluble gas such as the vapour form of ...
5
votes
0answers
99 views

Where can I get numerical data for the PAR (photosynthetically active radiation) curve?

I'm trying to do some rough figuring to calculating efficiencies of various light sources for growing plants. I'm hampered, however, by the lack of a curve to multiply by the spectrum of light ...
5
votes
0answers
300 views

Genetic expression in interspecific hybrids

Referring to interspecific hybrids, I have the following two questions:- Quoting from wikipedia:- The offspring of an interspecific cross are very often sterile; thus, hybrid sterility ...
5
votes
0answers
86 views

effect of background selection on promoter regions compared to distant enhancers?

Has anyone looked at the effect of background selection on the levels of conservation of promoter regions compared to distant enhancers? Do promoter regions have a higher conservation due to ...
4
votes
0answers
48 views

What causes humans to be physically weak compared to animals like gorillas?

Animals like gorillas seem to have a physical fitness and muscle mass that don't depend as strongly on how much exercise they get, compared to humans. E.g. gorillas living in the wild sleep and rest a ...
4
votes
0answers
84 views

Why do mammals produce more carbon dioxide than insects?

I understand that mammals produce more carbon dioxide than insects on a gram per gram basis, but why is that? I'm thinking it might be because mammals are warm-blooded, which require more energy ...
4
votes
0answers
32 views

How do disulphide bonds in hair cause curling?

I understand that the asymmetrical distribution of disulphide bonds in hair cause curling, but do not completely understand why this causes an inherent curl on the macroscopic level, for several ...
4
votes
0answers
37 views

Aquarium snail identification

Many of these little snails suddenly appeared in our aquarium from nowhere. I suspect that some snail eggs hitched a ride with some recently purchased plants. Can anyone identify the species? I am ...
4
votes
0answers
36 views

Insect identification, Bangalore India

can anyone identify this insect? It was sitting on my refrigerator Size: approx 1 cm height, 1 inch across My location: Bangalore, India
4
votes
0answers
44 views

Do “scars” in humans replace all the skin layers or only some layers?

When someone has a cut or surgical incision that results in a "scar", is the scar tissue replacing all 3 layers of the skin (epidermis, dermis, hypodermis)? Or only the first one or two of them?
4
votes
0answers
16 views

Why sympathetic and parasympathetic nerves originate in different parts of CNS?

Curious if there is a reason for having: parasympathetic nerves originating from brain stem and pelvic part of spinal cord sympathetic nerves originating from thoracic and lumbar parts It looks ...
4
votes
0answers
18 views

Do evergreen trees have higher densities of stomata to compensate for retaining leaves?

According to literature (Walls-Thumma), evergreen trees have less stomata on their leaves (than deciduous trees) to limit water evaporation. Does this mean they have less less stomata in total, or do ...
4
votes
0answers
28 views

Can we predict a person's tolerance to cold exposure during excercise?

Being an amateur athlete and student of anatomy I've always wanted to know if there is a formula for determining an unconditioned body's tolerance to cold temperatures while exercising. I know the ...
4
votes
0answers
43 views

Why aren't gene drives extremely common?

The ability for gene drives to sidestep the Mendelian mechanism and rapidly spread through populations (even if the gene is slightly fitness reducing) is extremely powerful. Why aren't normal ...
4
votes
0answers
148 views

Are there animal species with sex of an offspring determined by sex of preceding offspring?

For instance, if an animal's first offspring is male, then all subsequent offsprings will be male too (the sex of first offspring could be determined randomly). Does it happen in any species?
4
votes
0answers
34 views

How “old” is a specific snake venom?

This is a World Building question, but it's biology specific (I think). I'm looking for an approximate answer on how long, evolutionary, a specific venom has been roughly the same. Is it pretty much ...
4
votes
0answers
38 views

Is the fingerprint regenerated?

Let's say you get a a cut on your finger. Will the fingerprint be regenerated to matched your original fingerprint and if so, how?
4
votes
0answers
56 views

Why and how is DNA synthesis so much faster then RNA synthesis?

DNA synthesis in E. coli is 20x faster than RNA synthesis at 1000nt/s vs 50nt/s. (Mirkin'05) I find that perplexing since DNA polymerization has better proofreading than the RNA variety, which ...
4
votes
0answers
32 views

Why do some Brown Pelicans have orange or reddish parts on their bills?

I am doing research on Brown Pelicans and have photos/descriptions of the breeding and nonbreeding appearances of adults, esp. the California and eastern subspecies here on our southern Pacific, Gulf ...
4
votes
0answers
102 views

Why are lips covered with specialized skin?

I found out some interesting facts while studying our lips: They are covered in glabrous skin, while most of the skin surface is hairy; The outermost layer (stratum corneum) of the skin is far ...
4
votes
0answers
39 views

How does drug-induced photosensitivity work?

Some drugs (tetracyclines, for instance) can cause photosensitivity reactions—that is, some patients become extremely sensitive to the sun, developing rashes or inflammation after spending time ...

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