Tag Info

Hot answers tagged

20

Independent assortment. Mendel showed that his genetic markers for different traits, or phenotypes are transmitted randomly to the F1 generation. This was before the concept of linkage was discovered, so fortunately he selected unlinked genes. Segregation of alleles. The dominant and recessive alleles segregate away from each other when the germ cells are ...


5

Usually not (as described in the other answer, non-contiguous pieces of DNA are not considered as a part of a single gene). However there are some cases of trans-splicing in which the spliceosome can splice together RNAs arising from different genomic locations. But these are rare and do not have a direct effect on distinct phenotypes such as eye colour, to ...


4

Short answer Human females do not benefit much from an extra cone class, as color discrimination is hardly affected in most tetrachromats. In fact, tetrachromats often show increased error rates in their color discrimination. In dichromatic New World monkeys the heterozygous females do functionally benefit from their extra cone as they gain trichromatic ...


4

It sounds like you have considered most of the obvious alternatives (and thank you for clarifying the question). I suppose the first question in an alternatively spliced transcript with a retained intron is whether the open reading frame of the protein is maintained. If there is a termination codon that now becomes in-frame due to the intron then the ...


4

Qiagen and Life Technologies call it RNA content, total RNA, or total cellular RNA.


3

Your claim that "there is a lack of genetic diversity" in mitochondria is not correct. There is no connection between recombination and mutation rates per se. In fact, mitochondria have much higher mutation rates than nucleus and different types of mitochondrial DNA can even co-exist in one organism, a phenomenon called heteroplasmy (which is found at a ...


3

In XY sex determination systems the females carry two copies of the X chromosomes, thus can be homo- and heterozygous. Males however, carry one X chromosome, meaning that all loci are hemizygous (excluding those with homologs on the X). Under conditions of complete dosage compensation, often through up-regulation of X linked loci, they are effectively ...


2

If you think about it, monarchs must have a pretty strong genetic component to migration since often they only make one round trip at most in a lifetime. But its not as simple as passing a map in the DNA. If a mountain springs up on the route, the 'common sense' of the butterflies are still operational and they will tend to find their way around it. ...


2

To fully comprehend the concept of wobble base-pairing we need to consider the nucleotide sequences of the anti-codons in the tRNAs that have to "read" the genetic code when the mRNA is being translated on the ribosome. The nucleotide in the anti-codon's wobble position is, for example, often inosine. Under the rules for wobble base-pairing an Inosine can ...


2

Reiterating the above comments. Have a look at Tajima's D. It provides an estimate for the number of segregation sites for a population under a neutral mutation model. The general form of the estimation for a diploid population is $E[S]=4N\mu\sum_{i=0}^{n-1} \frac{1}{i}$. Here the mutation rate of is per-genome not per-site, so $\mu=L * 10^{-9}$ where $L$ ...


2

The fraction of polymorphic sites that exist in a population is dependent on the biology of the organism. For instance, you would expect to find different rates of polymorphism in related plants that have different breeding systems, e.g. in Silene [1]. Past bottlenecks are also expected to decrease polymorphisms [2]. So, the answer to your question would ...


2

The short answer is the transcription machinery will only bind on the correct orientation. The binding of proteins and such to the promoter DNA strand is determined by the sequence of the DNA, the sequence is not correct on the anti-sense strand for a given gene.


2

It could be difficult for RNApol to access genes inactivated because inactivated genes are often tightly packed by chromatin. Many genes have enhancer elements(specific DNA sequences) as well as TATA, and transcriptional enhancers, which are proteins, would recognize enhancer elements in a sequence dependent manner and loosen chromatin structure to make ...


2

Some suggestions. For identifying function do a homology search. There is little functional annotation of lncRNAs. So homology based information can be obtained only for protein sequences. So you can try these: Check the coding potential. Find ORFs (perhaps set a minimum length cutoff). To be stringent you can also check for Kozak consensus sequences (for ...


2

Units of genetic distance It took me a little while to understand what MU means. I have never seen MU but rather m.u. for map unit, or cM for centiMorgane. Solving the problem This problem got me thinking a little bit. My logic is the following: Probability of being heterozygous at the first locus You cross two individuals (we'll call them individual 1 ...


1

These two concepts are not mutually exclusive. You have constructed a false dichotomy. Both of these facts are true: The electrons in the pi orbitals of the conjugated double bonds in the planar rings are hydrophobic. The nitrogen and oxygen molecules (either in the rings, or as substituents on the rings) can participate in hydrogen bonds. There are ...


1

No, a gene is confined to a single chromosome. A gene is characterized by a start sequence in the DNA (among many other things), which indicates that the nucleotides are to be read and transcribed to RNA. This stretch of DNA in the gene is contiguous, although some parts may be skipped in transcription. Because different chromosomes are physically distinct, ...


1

Allele is a variant form of a gene. How many alleles there are depends on number of copies of the gene and number of variants. In theory you can have 5 identical copies or single copy and single allele (Y-linked genes come to mind). Regulation is very complicated, I'll refer you to reading on recessiveness, dominance. Barr bodies also have to do with ...


1

A flower (or a person) has two alleles for a gene because it inherits one set of chromosomes from one parent and another, comparable, set of chromosomes from the other parent. Hence there are two copies of each gene, and so there are two alleles for each gene.


1

Either strand of DNA can be sense or antisense. SWBarnes2 posts that the "transcription machinery will only bind on the correct orientation" and that is indeed what determines which strand is sense. But note his important statement "the sequence is not correct on the anti-sense strand FOR A GIVEN GENE" (my emphasis). As you move from gene to gene, the ...


1

One of the reasons why DNA is double stranded--this means DNA has sense and antisense strands--is to make a copy. During transcription, RNAs are transcribed referring to anti-sense strand sequences--making base pairs with anti-sense strand. In other words, the sense strand does not do anything during transcription.


1

This is not a answer but rather a very long comment which obviously would not fit in the 600 characters limit of a comment. Welcome to Biology.SE. How to write a good post I think it is not a good habit to write about personal stories on a science site. It makes your post not very attracting to people who could answer. You should also avoid sentence ...


1

Not all animals are equally predisposed for domestication. To be easily domesticated, animal should have: Flexible diet - and not compete with humans for food Reasonably fast growth rate Ability to be bred in captivity Pleasant disposition Temperament which makes it unlikely to panic Modifiable social hierarchy Wikipedia link above has plenty of ...



Only top voted, non community-wiki answers of a minimum length are eligible