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Friday, December 28, 2018

On the accuracy of DNA predictions

I'm very impressed with the DNA test administered by They report that I have over 600 fourth cousins or closer but I have confirmed some even more distant relationships. See below for the most distant relationship that the DNA tests reveal.

In the vast majority of cases the people who share DNA markers with me have no family tree that's on so it's impossible to say for sure whether we are related. There are often clues based on who else shares our haplotypes but unless the person reveals their name and some of their ancestors that's all I can do. I usually contact those people who could hep me sort out some unknown relationships but I rarely get a reply.

Saturday, December 22, 2018

Most popular Sandwalk posts of 2017

I was looking at some of my posts from the past few years and wondered which ones were the most popular. I had previously identified the most popular post of 2016 but not the most popular ones from 2017 so here they are.

The one with the most views (7481) is a link to a video by Michio Kaku who tells us that humans have stopped evolving [Another physicist teaches us about evolution].

The one with the most comments (259) is a post about my attempts to teach a creationist about glycolysis and evolution [Trying to educate a creationist (Otangelo Grasso)].

The post that I'm most proud of is: Historical evolution is determined by chance events

Tuesday, December 18, 2018

My DNA story

This is the latest update from Their algorithms are getting better and better. This corresponds very closely to what I know of my ancestors.

Saturday, December 15, 2018

Alternative splicing in the nematode C. elegans

The importance of alternative splicing is highly controversial. In the case of humans, the competing views are: (a) more than 90% of human protein-coding genes are alternatively spliced to produce multiple protein isoforms, and (b) less than 10% of human genes are alternatively spliced and most of the splice variants detected are due to splicing errors.

In addition to this fundamental difference in how to interpret the data, there's a controversy over the meaning and significance of abundant alternative splicing, assuming that it exists. The consensus view among the workers in the field is that alternative splicing is ubiquitous and it explains why humans are so complex when they have only the same number of genes as "lower" species like the nematode C. elegans. This was the view expressed by Gil Ast in a 2005 Scientific American article on "The Alternative Genome."

Saturday, December 08, 2018

The persistent myth of alternative splicing

I'm convinced that widespread alternative splicing does not occur in humans or in any other species. It's true that the phenomenon exists but it's restricted to a small number of genes—probably fewer than 1000 genes in humans. Most of the unusual transcripts detected by modern technology are rare and unstable, which is consistent with the idea that they are due to splicing errors. Genome annotators have rejected almost all of those transcripts.

You can see links to my numerous posts on this topic at: Alternative splicing and the gene concept and Are splice variants functional or noise?.

Wednesday, December 05, 2018

The textbook view of alternative splicing

As most of you know, I'm interested in the problem of alternative splicing. I believe that the number of splice variants that have been detected is perfectly consistent with the known rate of splicing errors and that there's no significant evidence to support the claim that alternative splicing leading to the production of biologically relevant protein variants is widespread. In fact, there's plenty of evidence for the opposite view; namely, splicing errors (lack of conservation, low abundance, improbable protein predictions, inability to detect the predicted proteins).

My preferred explanation is definitely the minority view. What puzzles me is not the fact that the majority is wrong () but the fact that they completely ignore any other explanation of the data and consider the case for abundant alternative splicing to be settled.