Genome (book): Difference between revisions

The first chapter begins with a quote from [[Alexander Pope]] on the cycle of life. The very broad topic "Life" is also the topic of the chapter. Ridley discusses the history of the gene briefly, including our "[[last universal common ancestor" or "[[LUCA]]".

Ridley discusses the history of human kind as a genetically distinct species. He compares the human genome to chimpanzees[[chimpanzee]]s, and ancestral [[primates]]. He also points out that until the 19th Century, most scholars believed that there were 24 sets of genes, not 23 as known today.

This chapter discusses the interplay between early geneticists, including [[Gregor Mendel]], [[Charles Darwin]], [[Hermann Joseph Muller]] and [[Francis Crick]] among others.

The concepts of [[pleitropypleiotropy]] and genetic [[Scientific pluralism|pluralism]] are introduced. A brief history of the study of [[asthma]] is used as the case study. Asthma is related to as many as fifteen different genes, many on [[chromosome five]]. Specifically, this includes a change from [[adenosine]] (A) to [[guanine]] (G) at position 46 on the [[ADRB2 gene]]. The ADRB2 gene is related to the control of bronchodialation and [[bronchoconstriction]].

[[Robert Plomin]]'s announcement in 1997 of the discovery of "a gene for "intelligence" on [[chromosome 6]] is the foundation for this chapter's lengthier discussion of the genetic basis for [[intelligence]]. This included gene [[IGF2R|IGF₂R]] on the long arm of chromosome 6., This genewhich may also be related to [[liver cancer]]. Ridley continues his premise in this chapter that the use of simple [[genetic markersmarker]]s is inadequate to describe the complete function of the genome, or the causation of disease.

This chapter discusses whether the form and existence of [[language]] has a genetic component. In Specificallyparticular, "[[specific language impairment]]" asis possibly related to a gene on [[chromosome 7]]. Ridley discusses the scientific disagreement between Canadian linguist [[Myrna Gopnik]] and others regardingon whether this disorder relates to difficulties with [[grammar]] formulation, or is morea broadbroader intellectual disorder. Genome, at page 104-05.

Ridley contemplates [[evolutionary psychology]] using the genes [[Testis determining factor|SRY]] (on the [[Y chromosome]]), and [[DAX1]] and [[Xq28]] (on the [[X chromosome]]). The theory of genetic conflict and evolution is debated using the rhetorical question, are we bodies containing genes, or genes in bodies?

[[Richard Dawkins]]'s concept of the "[[selfish gene theory|selfish gene]]" is described by Ridley through a discussion of [[retrotransposons]]. This includes the behavior of the [[LINE-1]] and [[Alu sequence|Alu]] [[transposons]]. Further, Ridley discusses the possible purposes of [[cytosine methylation]] in development. The chapter also discusses how, through [[reverse transcriptase]], [[retroviruses]] like [[HIV]] copiescopy itselfthemselves to the human genome.

This chapter relates to how understanding the [[genetic code]] matches models for [[embryonic development]] among vertebrates. Ridley discusses [[Gap gene|'gap' genes]], [[Pair-rule gene|'pair-rule' genes]], and [[Segment polarity gene|'segment-polarity' genes]]. [[Homeotic genes]] and [[Hox genes]] are described briefly. [[Walter Gehring]]'s discovery of the [[homeobox]] set of codes in 1983 is related to an on and off [[switch]] metaphorically.

It might be possible to prevent or cure [[Alzheimer's disease]] and [[coronary heart disease]]. APO genes like APOE influence fat and cholesterol metabolism. The E4 allele of EPOE contributes to the plaque buildup of Alzheimer's. Genetic testing may help patients take early preventative action.

The sheep brain disease [[scrapie]] appeared to be infectious but did not involve a microorganism. The disaster of [[Creutzfeld-Jacob disease]] in humans was found to be caused by the PRP gene which produces a [[prion]] protein called a prion that aggregates into clumps, destroying brain cells. Ridley attacks the panicky handling of [[prion disease]] outbreaks by governments.

Eugenics a century ago, based on faulty knowledge of genetics, led to immoral actions by governments and the US Supreme Court, pushing through [[compulsory sterilization]] of people such as those with trisomy 21 which causes [[Down syndrome]]. Ridley discusses the conflict between society, in the form of the state, and the individual.

Ridley addresses the heated debate between [[genetic determinism]] and freedom. Children are moulded both by their peers (other children) and by their genes. He argues that behaviour is in the short term unpredictable, but "broadly" predictable in the long term.