7

Both. Many primates bite their nails. Some do not. It's not species specific. Chimpanzees, for example, usually bite their nails; some prefer to leave them alone. They do grow continuously, and nails not kept trimmed probably break off (looking at the thickness of those nails, I get the impression that this might be rather painful if they break too short.) ...


6

Homology means shared evolutionary ancestry. Sequence similarity is often used as a proxy for homology but inferences should be made with care. The similarity between two genes/proteins should not just be good but has to be statistically significant (metrics like E-value) for the two genes/proteins to be considered homologous. INFERRING HOMOLOGY FROM ...


6

Insects and vertebrates are extremely distantly related: they're on opposite sides of the oldest split among bilaterally symmetric animals. Their most recent common ancestor lived in the pre-cambrian and was almost certainly worm-shaped with no limbs at all. There's no way that insect wings are homologous to any body parts of vertebrates. The evolution of ...


5

Serine Protease Catalytic Triad This is classic example of convergent evolution in catalytic mechanisms. Shown below are chymotrypsin (4CHA, green) and subtilisin (1ST2, blue) aligned on their catalytic triads (Ser/His/Asp, darker colours). There is no obvious sequence or structural similarity. You can check out the MEROPS database for a list of protease ...


4

First of all, don't reinvent the wheel, search for annotated homologs first. Assuming you don't find them, the next step is: Collect the sequences of your query proteins (not genes) from one species in a multifasta file. Run a tBLASTn with those sequences against the genomes of all the other species of interest. Analyze. Look for HSPs with a certain level ...


3

Do multiple sequence alignment of your protein sequences. This will give you evolutionary relationship between your sequences.


3

How can a male fly be pure-breeding? A fly or any organism can only be pure-breeding for a certain trait, not all traits at once. If the trait-determinant allele is found on an autosomal chromosome, this is not a problem. If it's on a sex-chromosome (chr1 in flies), it is sex-linked, and therefore cannot be pure-breeding because it may depend on the sex of ...


3

In most* scenarios you will probably want to look at a comparison of proteins following some additional matching that considers more than a single gene/protein. Luckily, this is a very common problem and one can often look up homologs through existing reference databases such as https://www.ncbi.nlm.nih.gov/homologene Further, if genes are not present, ...


3

Yes, assuming you treat the term strictly. The term homologous implies that the most recent common ancestor had the trait, although it would be possible for the term to be used in error, when something thought to be a homology is actually not. If the trait is shared but the trait evolved separately twice, instead you would refer to it as an analogous trait ...


3

If you have a non-coding gene sequence (e.g. regulatory sequence) this answer should hold your solution: Background theory Firstly you must realize that PSI-BLAST is built for detecting "romote homologues", (i.e. those that have a very "distant evolutionary relationship" to your query) - from a database of sequences. It is therefore known to be a "...


2

There are lots of statistical algorithms that allow you to evaluate the similarity between two given sequences. For instance, blast allows you a rapid comparison between your sequence and other sequences in a database; while Clustal, with a similar functioning, allows you to compare a set of given sequences between them. They are very simple algorithms, but ...


2

Assuming you are using PSI-BLAST to recruit coding homologous nucleotide sequences to your query nucleotide sequence. Here's a work-around using PSI-BLAST itself: Translate your nucleotide sequence into amino acid sequence Run psi-blast to recruit matching homologous protein sequences Store the names or database IDs (e.g. genbank accession numbers) of ...


2

First check if your RNA sequences are described by existing covariance models (CMs) available in Rfam. You can do this using the Infernal package to search the Rfam database of CMs. For those RNA sequences which match an Rfam CM, you can then use that CM to search the sequence databases for additional matches. For those that do not match an Rfam CM, you ...


2

The ancestors of all jawed animals probably had pectoral fins [Ref]. This primitive feature is homologous to shark pectoral fins (fig. 1). The forelimbs of quadrupeds are evolved from the pectoral fins of lobe-finned fish (fig. 2), and the pectoral fins of whales evolved from the forelimbs of their mammal ancestors. Thus, these organs are homologous as one ...


2

They are analogous at to function. Whales derive from terresterial animals that "returned" to the sea. Evolution adapted the forearms to fins. Here's a great diagram: http://evolution.berkeley.edu/evolibrary/article/evograms_03 The bat wing and the bird wing are also analogous as to function. Their functional aspects evolved independently. But as forelimbs ...


2

Last common ancestor is about 97.5 Million Years Ago. TimeTree.org Pig vs. Human That being said, they are close enough to us that they are a vector for influenza viruses that are able to make the jump to human pretty easily. Also we use their tissue as a homologue for human in forensic research. We also use valves from pig hearts to replace defective ...


2

Hoxd12 and Hoxd13 are involved in the development of wings in birds (Vargas and Fallon 2004). pdm and aptorus are involved in the development of wings in insects (Williams et al. 1993, Averof and Cohen 1997)


2

This vocabulary is common in textbook but not in the peer-reviewed literature First please note that while those terms are often used in intro class to evolutionary biology, they are actually rarely used in the peer-reviewed literature. No trait value is fundamentally derived / ancestral Note also that any given set of shared trait could be called ...


2

To add to @S Pr's answer and provide another cool and useful fact, in some organisms, like birds, the males are the homomorphic sex (their sex chromosomes are the same size and haven't decayed like the Y has in human males), not the females (who are ZW, with the W being the analogue of the mammalian Y chromosome). So more generally, sex chromosomes can be ...


1

The general term "copies" has multiple meaning with reference to genes. In diploid organisms for example, we have two copies of each gene (except those on the Y chromosome). However, these copies are called alleles. Copies that are due to duplication are called parlalogs. There is no distance criterion for differentiating copies or parlalogs. Once duplicated,...


1

The evolution of new genes is frequently associated with gene duplication. The paralogous genes are then free to evolve on their own into new functions over time. Sometimes (usually) the paralog will end up with a frame shift, or stop codon that inactivates it. But your question is lacking the element of time. At the instant of gene duplication, each copy is ...


1

No, because it is really not a binary decision. There are attempts to associate percent pairwise difference with taxonomic ranks (particularly species), but this is problematic because every independent lineage can vary according to its own rate. You could use sequences from different families, or orders, or even phyla, but these two can depend on whether ...


1

I've never used T-Coffee but it looks like the web-server version gives you a total score as well as a score for each individual sequence; do you know if those numbers are related to the numerical descriptors you need? A good place to start would be to read the documentation. Another good place to look would be the Google Groups page for T-Coffee.


1

From Entrez Programming Utilities Help [Internet]: Input: Any Entrez text query (&term); Entrez database (&db); &usehistory=y; Existing web environment (&WebEnv) from a prior E-utility call To avoid the error messages, web1, and key1 can be used as terms (these are usually being used to associate with other searches), however this ...


1

Why some human beings bite their nails? Because, they are primates - it is inherited way to treat our nails, called onychophagia. While normal in some primates (and this is the way they treat their nails), it is considered abnormal in human.


1

1.Is such an approach trying to quantify homology? Which i know is not correct as homology is qualitive measure. A common approach to identify orthologs (homology between two genes resulting from a speciation event) it 'best bidirectional match': if you blast gene A (in species 1) against all genes of species 2 the best match is gene B, and if you blast ...


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