Hi Leah Avi-Isaac

what a good question.

just because of size and number of its genes, and their limited implications in cell metabolism that enabled them from evolution pressure?

low GC percent could have also an impact on genome evolution.

whereas on other chromosomes many genes had the possibility to evaluate in structures, complexity and size.

any other idea?

fred

Longer genes and more exons may contribute to transcription and translation accuracy. So what does the shorter transcripts mean ?

Dachao Xu Frederic Lepretre

Hi, thanks. I'd like to try to answer, in reference to this article:Article Gene Size Matters: An Analysis of Gene Length in the Human Genome

1. "It was hypothesized that, due to the great levels of expression in smaller genes, there is selective pressure to maximize protein synthesis efficiency (Urrutia and Hurst, 2003)."

Does this point goes in-hand with the fact that the mammalian Y chromosome is inherited hemizygously? I assume that the Y is under greater selective pressure, and its shorter transcripts reveal such.

2. "Gene length has been associated with biological timing. In response to stimuli, smaller genes produce proteins faster, and these smaller proteins often play a part in the regulation of longer proteins, which, in turn, are expressed later in the response."

I find this correlation weak, but let's move on. In regards to the Y chromosome, it makes sense with the knowledge that Y chromosome genes are highly involved in male-specific developmental functions, and so they must be precisely temporally regulated.

This is my answer, but I'd love to explore more.

The average length of transcripts on the mouse chromosome Y is generally shorter than those on other chromosomes due to the unique characteristics of the chromosome Y.

Chromosome Y is the smallest and least gene-dense chromosome in the mouse genome, with only a few hundred protein-coding genes. Most of these genes are involved in male fertility and the development of male characteristics. In addition, chromosome Y lacks most of the repetitive sequences and transposable elements that are present on other chromosomes, which can lead to the production of longer transcripts.

It is also worth noting that the gene expression patterns on chromosome Y are different from those on other chromosomes. Chromosome Y is generally expressed at lower levels than other chromosomes, and the genes on chromosome Y are often expressed in a tissue-specific manner. This may contribute to the shorter average length of transcripts on chromosome Y.

Overall, the shorter average length of transcripts on chromosome Y can be attributed to the unique characteristics of the chromosome and the patterns of gene expression on the chromosome.