From: Regis Zimmer uoguelph.ca>
Date: Sun, 24 Nov 1996 19:41:19 -0500 (EST)
To: Hans Ellegren <Hans.Ellegren bmc.uu.se>
Cc: mappersiastate.edu
Subject: Re: number of avian genes
Hans;
That's a very good question. Actually, I would personally think that
if the 1/3 representation of the genome is a true estimation, than it
must be mainly due to the coding DNA of the microchromosomes.
Incidently, some data is in agreement with the fact that the
microchromosomes comprise as much as 30% of the total chicken complement. At
the same time, there're some research supporting that most of the CpG
islands (i.e. transcriptionally active DNA that were estimated by the
concentration of sequences hipersensitive to DNAseI-digestion)
are present in the euchromatic DNA of the microchromosomes. On the other
hand, chicken macrochromosomes are known to have a lesser gene density than
their relatives in the mammalian genome. In this way, the
number of functional genes seems to be proportionally similar to the
mammalian genome. This is my personal oppinion ;-)
Regis Zimmer
Dept. of Animal and Poultry Science
University of Guelph
Guelph, Canada - N1G 2W1
On Sun, 24 Nov 1996, Hans Ellegren wrote:
> Hi,
>
> A figure of 100,000 genes is usually assumed for mammalian genomes, but is
> anyone aware of if the same number of genes is true for birds, eg. chicken?
> If so, the fact that birds have only about one-third of the DNA content of
> most mammals must imply that genes constitute a relatively higher share of
> the genome in birds than in mammals (I recognise that this is so for the
> chicken microchromosomes). In other words, if 5-10% of the human genome are
> genes, the proportion in birds would be 15-30%. Is this correct?
>
> Best wishes,
>
> Hans
>
> Hans Ellegren
> Department of Animal Breeding and Genetics
> Swedish University of Agricultural Sciences
> Biomedical Center
> Box 597
> S-751 24 Uppsala
> Sweden
>
> Voice: +46-18-174903 or +46-18-551318
> Fax: +46-18-504461
> Email: Hans.Ellegrenbmc.uu.se
>
>
>
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