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location Boston, MA USA
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visits member for 2 years, 9 months
seen Jun 13 '13 at 13:30

Mar
1
comment What makes a gene dominant or recessive
It is not the gene but the allele of that gene that is dominant or recessive. In addition, we do not contain two copies of each gene. Some genes exist at zero or one copy and others are somewhat to greatly duplicated - and this is considered normal (copy number) variation.
Dec
6
comment Can a human smell through the ears?
@terdon I wrote that expression of a olfactory receptor means there is the potential for that function and not an absolute, defined function.
Nov
1
comment Is there a circadian component to hunger?
This question demands an answer that is tissue specific. Leptin is produced by skeletal muscle as well as adipose. Production of a hormone or signaling molecule may be under circadian control in one tissue but not another. In addition, a complete answer will talk about aging as circadian rhythms in peripheral tissues break down with aging.
Oct
3
comment Since Darwinian times, has there been any striking/notable effects of evolution on humans?
Yes, the epigenetic, or Lamarckian, response is important +1. The environment - air/water quality, physical activity, availability of energy-dense food, antibiotics and other drugs - have all exerted influences on the epigenome.
Sep
28
comment What reasons allow for women to outlive men?
I'd also add that differences in the lifestyles of eunuchs compared to non-castrated men may influence these findings. Eunuchs likely had a special, maybe even pampered, role in society. The other men likely were engaged in dangerous work. Recall that industrial and work-related accidents was one of the top 120 killers (in the USA) well into the 20th century.
May
21
comment The evolution of dogs through domestication and artificial selection
+1 for the fox example! This shows how few genetic polymorphisms and how fast domestication (ie, taming) can occur. Other studies have shown that a few genetic polymorphisms can lengthen snout, shorten legs, alter other characteristics which are used to distinguish a breed of dog.
May
11
comment obesity risk and single gene polymorphisms
Yes, FTO is the strongest thus far in the populations thus far tested. If Asians or African populations were to be tested as deeply, as often as European populations, other genes certainly may be added to the list.
May
11
comment Is there any difference in terms of personal healthcare between complete DNA sequencing and SNPs genotyping?
Sequencing gives the researcher data on rare or private mutations that are not on the genotyping arrays.
May
8
comment Primary function of the enzyme lipoprotein lipase
No. All cells need fats, primarily to build membranes and to store in vesicles for later conversion to energy. Storage is not restricted to adipocytes.
May
1
comment Linkage and LD: quantitative or qualitative?
This is a good explanation with a fine example. It can be added that the r^2 value can be between 1 (complete LD) and 0 (zero, no LD whatsoever as with markers on different chromosomes). Yes, we and many others use a cutoff of r^2 > 0.8 to denote strong LD. However, values of 0.4 and above are not to be discounted as having no LD.
Apr
26
comment How many genes do we share with our mother?
I like the physical vs abstract take on this.
Apr
26
comment How many genes do we share with our mother?
Nice answer, +1. Actually, recent analysis of 1000 Genomes data shows that each person has some 25-40 homozygous LOF (loss of function) variants not found in either parent. Thus, one could lower the 100% figure to ~99.9% shared.
Apr
23
comment Mouse meta-globin mRNA problem
A) Is this a take-home exam question? 1) Yes, then I can't answer your questions for you. 2) No, well, I'll see if I have time tomorrow to get to it.
Apr
17
comment What's the aim of genetically modifying of foods/organisms?
I believe that there is a GMO potato now grown in Europe for paper production.
Apr
16
comment What's the aim of genetically modifying of foods/organisms?
There's also a similarly modified cotton plant. While not nutritious, this cotton can be cheaper to produce. A GMO cotton could be engineered to require less treatment to make cloth, with lower environmental impact. I don't think the golden rice actually had very much bioactive vitamin A per serving.
Apr
13
comment Mechanics of going from DNA sequence to metabolic network
In general, assignments of function are based on sequence similarity (tools like BLAST) - comparing protein sequences to those with known or demonstrated function - or identification of functional motifs as in the Pfam, SMART, INTERPRO and others (ca.expasy.org/tools).
Apr
9
comment Are there differences in DNA between humans of today and humans from 2000 years ago?
I did not imply that the epigenetic changes are heritable. The environment changed over the last 2000 yrs and some of those changes are constantly acting upon the genomes of successive generations. The question asked about a comparison of a current human genome with one from 2000 yrs ago. Because the environment is different, I expect that population-wide we would see differences in epigenetic marks.
Apr
6
comment Why do some fruits have a much wider range of acceptable sizes than others?
It's fine as one question. Each aspect of jmusser poses here informs the other. It's all related.
Apr
4
comment Are there differences in DNA between humans of today and humans from 2000 years ago?
Exactly, I wouldn't understand down votes either. "[D]ifferences in the genome" is a legitimate question. While one may at first think of sequence changes, and some mitochondrial and Y-chromosome haplogroups may have arisen within about 2000 yrs ago, changes at the level of methylation, acetylation and other levels fits the question.
Apr
3
comment What is the advantage of using starter cultures for growing bacteria?
If a culture is too dilute, it can have a reduced doubling time.