Hot answers tagged human-genetics
9
Actually it is a very important question for laboratory animals (and, I imagine, endangered species) and was calculated to be 25 couples.
With any number of animals (including humans), there is always some inbreeding happening, but you can reduce it with the number of breeding pairs and careful pairing. When you get to 25 pairs (50 animals) and have ...
9
I thought it was just that the other aneuploidies were fatal. They occur as often but miscarry earlier in the term therefore you don't see them. So basically there are only three that are viable 21,18 and the sex chromosome with a number of combinations: XO, XXY, XYY and XXX.
More information here:
...
8
This difference would have the greatest impact on treatment for cancer, in which a treatment protocol is based on genes deleted, amplified, altered in the tumor vs the reference genome for that patient.
In terms of health risks based on SNP genotypes, the data are far from complete. Sure, some level of risk can be assigned to a variant (SNP), say at certain ...
8
I very much agree with bitwise's answer. I just want to point out that even in terms of nucleotide sequence there are some extremely conserved genes.
The most highly conserved are ribosomal RNA genes. The image below shows the conservation of 16S rRNAs from archaea, bacteria, and eukaryotes (eukaryotes do not have 16S in their cellular genome but the gene ...
7
Depends on what you mean by unchanged. If you mean a gene that maintained the same nucleotide sequence, then the answer is no.
If you meant a gene that descends from a very ancient gene, i.e. one can find orthologs in very distant species, then the answer is yes. Many of the basic molecular systems are relatively conserved, including several metabolic paths ...
7
That would be hard to say because really beneficial mutations become well distributed through the genome. Basically the differences between us and chimpanzees are a catalog of all the beneficial (or completely neutral) mutations since the ~4.7 M years since we diverged from each other.
Separating them from changes which have no special effect would be ...
6
Just continue scrolling down wikipedia: there are also listed two examples of beneficial mutations: the one conferring HIV resistance, and the one conferring malaria resistance.
Note that 'beneficial' is relative. The mutation associated to malaria resistance is actually causing sickle cell disease.
6
A major limiting factor in such an exercise is the complexity of the biological process under question (eye colour etc.,) and thus, our nascent understanding of these. What I mean is that there is not a single gene that determines a given characteristic, rather it is the complex interaction of a set of genes in different conditions responding to ...
6
Another list of simple human traits can be found on the Western Kentucky University site.
I will ask also AB0 and Rh Blood Groups, you can use this also to check associations with other genotypes/phenotypes, see this stackexchange question
If you are going to sequence also the mitochondrial DNA, you may want to reflect on questions to ask also about their ...
6
Bone Marrow transplants are extensively matched in order to prevent rejection. Current matching methodology is HLA matching: Stanford Children's Hospital Guidelines
How are a donor and recipient matched?
Matching involves typing human leukocyte antigen (HLA) tissue. The antigens on the surface of these special white blood cells determine the genetic ...
5
Gene frequencies (frequencies of each allele at a given loci) in populations are affected by many things divided in to systematic and dispersive processes. Systematic process (migration, mutation, selection) affect gene frequencies in an often quite predictable manner and strength. Dispersive process (Random drift, differentiation between sub-populations, ...
5
Polyphasic sleep can allow people to sleep at multiple regular intervals throughout the day and allows people to get by with less total sleep. I don't know of any training that can help people reduce the amount of monophasic sleep they need without a negative impact.
5
23andMe is a company that provides sequencing. Before they sequence your genome, they ask you to fill in a couple of surveys, one of which is about your physical features. Here is a list of some of the questions they ask:
How much hair do you have on your upper/lower back?
When you walk, in what direction do your feet naturally face?
Do you have ...
5
Meiosis is the type of cell division responsible for the diversification of genetic material among egg and sperm cells. The diversity comes primarily from crossing over (Prophase I) and the cell divisions (Telophase I & II) later on in the process.
Meiosis begins with one diploid cell containing two copies of each
chromosome—one from the organism's ...
5
Many genetic studies in this area have found that variation in serotonin receptors associates with differences in a number of personality traits. That one gene, or a very small number, turns up time and time again for something so complex as human personality makes me a bit suspicious.
Other factors at play:
Family dynamics
Culture and cultural norms
...
4
The problem you are looking for is called the "Nature vs nurture" debate. Lots of scientists have written lots of books and papers and done lots of studies on the subject. As you can see, the title of the debate already includes the two main concerning factors: nature (genes) and nurture (environment).
These of course each include a variety of ways in which ...
4
Others have posted that the term beneficial in genetics is contextual - single mutations may be harmless, unless another mutation is co-inherited; this is called epistasis (where more than a single mutation/genotype/allele is required for the phenotype).
I have not studied the list comprehensively, but there is a 'catalog' of all robust genome-wide ...
4
One that I wish we asked the subjects in our studies is: When do you normally go to sleep each evening and when do you normally wake up? This can get more detailed, but these 2 basic questions can allow segregation into morning or evening types (or both).
Deep phenotyping is critical to a better understanding of the genetic influence on disease risk ...
4
It is mainly determined by the OCA2 gene, but it also likely involves several other genes, including TYR, TYRP1, HERC2, and several others. To complicate things further, it is not a "mutant/wild type" trait, but multiple normal alleles can be found in the population, and it is believed that the sum of these single nucleotide polymorphisms (SNPs) determine ...
4
One possible scenario would be that a particular woman develops a mutation rendering her much more 'fit' (in the evolutionary sense) than her peers. For the sake of argument, lets take the very simplistic case of an X-linked recessive mutation causing the women who bear it to have say 10 children at each birth. If this mutation is then transferred to the ...
4
When talking about a maternal unbroken linage and a paternal unbroken linage, is the meaning that Mitochondrial Eve had a linage of only women reaching every person today, and the same with Y-chromosomal Adam and men?
Kind of, yes. The concept behind Mitochondrial Eve and Y-Chromosomal Adam has to due with cell replication and basic genetics.
The ...
3
Using a somatic cell in an a ovum is what is typically done in the process of cloning. It was the same process used to create Dolly the Sheep. What you're asking about is something very different:
Consider that somatic cells are properly diploid. Whereas an ovum itself just contains a haploid number of chromosomes. In typical sexual reproduction the sperm ...
3
In bacteria, this is often true. This is because more than one gene is often transcribed onto a single RNA. This grouping of genes is called an operon. It is usually true that these have a related function because they are being translated to protein in very much the same proportion - a convenient way to regulate the function as a whole.
Once you get ...
3
The theory of natural selection has it that individuals with better genes tend to survive and reproduce, passing their genes to their offspring.
Yes, under selective pressure, that is. The stronger the selective pressure, the more the population will change. Without a selective pressure, there isn't an impetus to change.
However, due to the ...
3
There is a nice page that tries to explain this:
The known Human Eye color genes are: EYCL1 (also called gey), the Green/blue eye color gene,
located on chromosome 19 (though there is
also evidence that another gene with similar activity exists but is
not on chromosome 19). EYCL2 (also called bey1), the central brown eye
color gene, possibly ...
3
The processes that control the germline of metazoans (multicellular animals) are highly regulated compared to single cell bacteria and eukaryotes as well as plants.
At this point there are no clear stories of gene transfer into a complex animal, though there are some for plants:
"animals and fungi seem to be largely unaffected, with a few exceptions, ...
3
I would think there have to be, though do you mean collecting samples on a regular basis and plotting out the difference at each point? Or do you simply mean the total accumulated change. If it is the latter, the answer is certainly "yes". You have probably seen the Nova documentary "Ghost in Your Genes" (The US, not BBC one). In it they show comparison of ...
2
Genotyping only tests for SNPs in predetermined locations. If you have SNPs in other places in your genome, genotyping won't tell you that, but whole genome sequencing will (by comparing your genome to a reference genome available at NCBI). Also, there are other variants such as copy number variations, repeats, insertions and deletions that genotyping can ...
2
Some other ones:
Are you a Singer? :-) AVPR1A and SLC6A4 Polymorphisms in Choral Singers and Non-Musicians: A Gene Association Study http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031763
Do you have sunbed sessions?
Do you dance? (via C.Dina. ) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1239939
2
One thing still missing from the other answers: How many genes? One answer: about 6400, i.e. ~30% of all human genes can be traced back to LUCA.
To come up with this number, I used the eggNOG database of orthologous groups. This database contains clusters of proteins that are probably homologous. So I checked how many human genes are in clusters that also ...
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