Tag Info

Hot answers tagged

11

Theoretically... 93 million bp/cell x 650 daltons/bp x 10^13 cells/body x 1.66 * 10^-27 kg/dalton = 0.001 kg So I would say it's not too much of a difference :P


10

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: ...


7

Again, not an expert, but I found this article seems to say it pretty well: Telomere's are most commonly measured by qPCR of the repetitive regions with degenerate oligomer sequences such as "TTAGGG and CCCTAA repeats" Although articles like this one appear to advance measurements in vertebrates, this reference from 2011 implies two techniques continue to ...


5

Here is a paper you might want to take a look at: Phylogenetic Origin of Human Chromosomes 7, 16, and 19 and their Homologs in Placental Mammals From the abstract: From their origin, these chromosomes underwent the following rearrangements to give rise to current human chromosomes: centromeric fission of the two submetacentrics in ancestors of all ...


5

@nico is right. the number of chromosomes is the result of an evolutionary timeline, puncutated by sometimes spontaneous events which shape the DNA. These events occur in the course of evolution: 1) Chromosomal rearrangements. Large sections of the genome can flip around or become integrated in other chromosomes. By homologous recombination, regions of ...


4

I think the OP is asking why we have one less chromosome pair than chimpanzees (for example) [23 pairs instead of 24]. The is an abundance of evidence, as alluded to above by shigeta, that human chromosome 2 is the result of a telomere-to-telomere fusion of two ancestral chromosomes (IJdo et al., 1991). This event did not occur in our closest ancestors, ...


4

Answer An comprehensive online database of the chromosome numbers of all living species most likely doesn't exist. This Wikipedia article is the best and most complete reference comprising animals that I can personally find on the internet. This source in Spanish, which I've translated with Google Translate reads: Canedo Delgado (1999) performed the ...


3

Since you didn't specify animals, I will add here for anyone coming from google that plant chromosome numbers are stored in the Index to Plant Chromosome Numbers. I would be surprised if such a database exists for animals (except maybe insects) as historically C-numbers of plants and other cytogenetics were important for taxonomy (and still is important), ...


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 ...


2

It is generally known that the smaller (or less complex) an organism is, the more "condensed" it's genome is. For example, bacteria (or some eukaryotes) have operons (http://en.wikipedia.org/wiki/Operon) or overlapping genes using different and they don't have introns, which alltogether saves a lot of space. There are many reasons for that. Available space ...


2

The simple answer is that which X chromosome is inactivated varies in different cell lineages, so typically a female will have cells exhibiting either wild-type or mutant phenotypes. It was Mary Lyon's observation of mosaicism in heterozygous mouse coat colour that gave the phenomenon its name. So in the case of a recessive disease there will be a phenotype, ...


2

The number of spindle fibres is actually more than total number of kinetochore pairs. The fibres attached to kinetochores are called K-fibres and the others are called polar fibres. I cant surely say that there is exactly one K-fibre per kinetochore but as per its definition and from the microscopic images you can conclude that there is one per kinetochore. ...



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