The scientific study of the structure and function of genes at the molecular level, particularly chromosomes and DNA.

learn more… | top users | synonyms

1
vote
0answers
66 views

What type of point mutation and chromosomal mutation cause Albinism in humans?

First of all, I know that OCA1 (Oculocutaneous Albinism Type 1) is autosomal recessive which means that both parents-who are unaffected-have to pass down one copy of a mutated gene in order to ...
5
votes
1answer
92 views

Why are fifth order Markov Models, the ones most often used for gene prediction?

As far as we know that smallest polypeptide chain length is 60 amino acids - so if we found an Open Reading Frame (ORF) of about 60 codons without the interruption of stop codon we can consider it to ...
4
votes
1answer
568 views

Genetic linkage greater than 50 centimorgans

Classically, the linkage between two loci can be measured in centimorgans (cM), which represents the percent chance that these two loci will recombine an odd number of times (generating a recombinant ...
3
votes
2answers
82 views

Crossing over and exon shuffling?

Campbell Biology 10e, in discussing the functions of introns, writes: The presence of introns in a gene may facilitate the evolution of new and potentially beneficial proteins as a result of a ...
1
vote
0answers
21 views

XNAs as a Genetic material [closed]

I heard there is a new genetic material called XNAs.I wanted to know more about this.Does anyone about XNAs as genetic material?
3
votes
1answer
78 views

What came first? The DNA or the DNA polymerases?

I know this sounds a lot like chicken and egg question and while the latter has an answer, I am intrigued about the former. A modified form of the question would be, in the course of abiogenesis, ...
0
votes
1answer
47 views

How does a test like the Natera Panorama distinguish the child's genome from the mother?

Blood tests on an expectant mother, like the Natera Panorama, are now being used regularly to screen fetuses for chromosome abnormalities. At my wife's recent prenatal visit, she wasn't really even ...
0
votes
0answers
22 views

Amplified Fragment Lenth Polymorphism (AFLP) primers

I am trying to blast AFLP primer sequences to the genome to find the locations of the AFLP markers. However, I can't seem to find full alignments for the primers on the genome. For example, in the ...
1
vote
2answers
66 views

Explain allelic complementation at molecular level

I know that Allelic complementation is a phenomenon where two recessive loss-of-function allele generate a functional gene product by compensating each others' defect. But I don't get how do they ...
0
votes
1answer
47 views

probe amplification in MLPA

I'm reading an article about MLPA (Multiplex ligation-dependent probe amplification) and I got stuck on this sentence: The advantage of splitting the probe into two parts is that only the ...
3
votes
2answers
337 views

Gene and alleles

This is a multiple choice question: Consider a gene, ABC, which codes for an enzyme involved in the metabolism of sugars. There are two known alleles of this gene, ABC1 and ABC2. Which statement ...
3
votes
2answers
52 views

ChIP-seq for histone modification not in agreement with RNA-seq for expression

I have ChIP-seq for H3K79me2 and H3K36me3 and RNA-seq data for treated and untreated samples. Those two histones mark active genes. Lets say, hypothetically, a peak caller finds differential sites at ...
1
vote
0answers
30 views

Is DNA transcription inactive during mitosis ie no proteins are made? How does the cell survive?

I've read that during mitosis, DNA exists as heterochromatin, a form that is unable to be accessed for transcription. Does this mean no new proteins are made during what can be 20% of a cell's life? ...
5
votes
1answer
29 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
1
vote
1answer
39 views

Are the genes for transcriptional factors close to their targets in the genome?

Transcriptional factors (activators and repressors) are proteins which regulate transcription. Being proteins, they themselves are also made from expression of certain DNA sequences/genes. For ...
7
votes
3answers
5k views

Why does replication require primers while transcription does not?

In transcription, there is no need for any primer. I guess the basic mechanism of DNA polymerase & RNA polymerase is the same. So why does replication have the need for a primer?
1
vote
1answer
60 views

Chromosomomal walking

I'm having a great deal of trouble understanding chromosomal walking, especially in regards to this article: Control of male sexual behavior and sexual orientation in Drosophila by the fruitless ...
2
votes
1answer
42 views
1
vote
1answer
286 views

Operators and Enhancers/Silencers

Wikipedia has two images, of a eukaryotic gene and of a prokaryotic gene. They show the difference that the prokaryotic gene also has an operator while the eukaryotic gene does not. Both also have ...
1
vote
0answers
23 views

Degenerate primer designing software

Can any one provide online free degenerate primer designing software. I have tried couple of them like CODEHOP is one where BLOCK formatting step finding difficulty, can anyone help me out....
5
votes
1answer
84 views

How many genes does D. melanogaster have?

Obviously there is no 100% exact number, but I came across this on flybase, the gold standard for annotation. I am confused now. "Genes located to the genome", is that what I am looking for? If so, ...
2
votes
1answer
28 views

ATP to disassembly of nucleotide ratio

DNA Helicase, the enzyme that is responsible for tearing apart the strands before DNA replication, requires ATP to rip apart nucleotides. I have asked this question to several professors and they ...
1
vote
0answers
38 views

“Signal Advance”: Unsure of meaning or contextual use

I am reading through Recombinant DNA; Genes and Genomes - A Short Course - Third Edition by James D. Watson, et. al. and I came across this paragraph in the discussion about discrete factors of ...
2
votes
1answer
40 views

How to find conserved residues across species?

I want to identify if certain phosphorylation sites are conserved for protein X across humans and yeast. I know from MS data that there are 4 phosphorylation sites in Human protein X. In order to ...
1
vote
1answer
36 views

gene transformation from plant to plant - transgenic plant

I want to know if the expression of a transfered gene depends on source of the gene, if e.g.: 1] I isolate a gene from plant and transfered it to the same plant? 2] I isolate a gene that is highly ...
12
votes
3answers
2k views

Does a man contain all the genes needed to make a woman?

This question is brought on by a Sci Fi novel I am thinking about writing. The plot device involves a colonist in charge of building a population on a new planet who loses his supply of embryos and so ...
1
vote
1answer
22 views

Degree of complementarity

Apologies in advance for asking bit naive question. I have looked up for this concept a lot but didn't find anything. The wikipedia (I know its not authentic all the time, but I think works well for ...
2
votes
1answer
21 views

When performing mutagenesis for an assay, how do you decide on the sample size of individuals to be mutated such that all genes are covered?

If I want to study, say, gustatory response of salmons to a bile acid, I need to mutagenize a sample of salmon males. However, given that there are many genes involved in this response, what is ...
2
votes
1answer
86 views

What does it mean to clone a gene?

When I look up information related to the identification of disease genes, texts will often refer to the gene being "first cloned." What does "clone" mean in this context? Is it simply a synonym for ...
2
votes
0answers
41 views

PCR that worked previously is now only showing primer dimers and a smear on gel

PCR amplification of a promoter sequence for gel extraction worked beautifully using Phusion HF enzyme with GC (higher error but less picky) buffer. However, DNA concentration from the gel extraction ...
2
votes
1answer
30 views

genetic complementation problem

I've attached the picture of the problem. SO, based on the information I managed to assemble two large cistrons. (if the combination of two mutants yield (-) mutations are on the same chromosome) ...
1
vote
0answers
35 views

Can genes be expressed sequentially?

As I understand it, any gene on an exposed/unpacked region of a chromosome is continuously being expressed. Regulatory genes may increase or decrease the amount of protein synthesised due to its ...
5
votes
1answer
341 views

Lac operon: How can lactose enter the cell in the absence of lactose permease?

My textbook states that lactose permease...transports lactose into the cell and When lactose is added to the growth medium, the lactose molecules bind to the other site on the repressor ...
1
vote
1answer
2k views

Calculating number of amino acids in mRNA

Assuming there were 20 different amino acids and less than 40 types of different tRNAs found in this alien organism. How many amino acids would be found in the translational product of a ...
2
votes
2answers
117 views

Alternatives to PCR

PCR uses cycles of heating and cooling to denature the strands, calling for special thermostable DNA polymerases. In a cell, during replication, Helicase unwinds the DNA without the requirement of ...
3
votes
2answers
216 views

How does Cro protein expressed by lambda phage kill its host?

I read that the DNA segment of lambda phage integrated in host DNA could switch between lysogenic state where cI represses the expression of Cro and lytic state where Cro expression takes over and ...
1
vote
1answer
53 views

tandem repeat sequence; causes of contraction and/or expansion question

Question: Which of the following events, occurring within a tandem repeat sequence, will cause an expansion or contraction of the array? A) Endoduplication B) homologous recombination C) ...
1
vote
0answers
91 views

mutations induced by transposons

Question: In contrast to chemically-induced mutations, mutations induced by transposons are more likely to ... be lethal de dominant be stable revert to wild types be a gain of function The ...
1
vote
0answers
28 views

recombination between DNA segments question

In the diagram shown above, segments A and C are copies of a repeated DNA sequence, flanking a unique stretch shown as B. A and C are in an inverted orientation relative to each other, as indicated ...
6
votes
0answers
133 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 ...
3
votes
3answers
125 views

Abbreviations for molecules: What are CheW, CheA, CheY?

I've encountered the abbreviations such as "CheW" and "CheA" for certain organic molecules. For example: Proteins associating with the Tar complex include the autophosphorylating protein kinase ...
0
votes
0answers
7 views

Double stranded breaks in E. coli

What could be a possible reason why no enzymes have been found that make double stranded breaks in the RecBCD pathway?
0
votes
2answers
116 views

how do I find the number of bp in chromosome 3 by knowing number of bp in chromosome 1?

If i have a number of bp in chromosome 1 for example(298,295,559 bp) can I use this number to find the number of bp in chromosome 3.
19
votes
2answers
1k views

How does RNA transcription know which half of the DNA to use?

I feel that I might have a complete misunderstanding here. If DNA has two strands, how does RNA transcription know which one to choose?
9
votes
3answers
326 views

Splice in with CRISPR/Cas

I need to splice a gene into a human cell genome, with highest rate possible. I mean, doesn't really matter where the gene enters, nor does it matter if some cells die as a result of this. CRISPR ...
-2
votes
1answer
47 views

DNA Replication And Primer [duplicate]

Why does nature rely on RNA primer for the start of DNA Replication? Why not simply use DNA primer and make life simple !
0
votes
0answers
46 views

Why is dsDNA nuclease activity by CRISPR/Cas9 only shown indirectly?

In Jinek et al., the authors show nuclease activity of their CRISPR/Cas9 system using the so-called Surveyor assay method. This assay recognizes small mismatches in dsDNA which are introduced by error ...
0
votes
1answer
137 views

Layman definition of genetic polymorphism?

I am reading an article about Genetic Polymorphism and there are lines in the article about genetic polymophism that I don't quite understand like. In this area, there are six different chemotypes ...
1
vote
0answers
47 views

How does intron retention make the alternative transcript non-coding?

I faced with a non-coding transcript that specified as one the isoform of BIN1. It sounds that this isoform generated as a result of alternative splicing with a intron retained; am I right? However, ...
1
vote
1answer
218 views

How do DNA-binding proteins determine that they're binding to the correct DNA base pairs?

My professor posed this question to the class today - "How do DNA binding proteins specifically bind to base pairs?" He alluded to the different arrangements of hydrogen-bond donor and acceptors in ...