1	Individuality, Genetics and Environment What makes each of us the way we are? Can one separate the contributions of genetics and the environment and interactions between them?
2	Reading Assignment Chapter 15, but only 15.1, ‘What do genes do?’ Section 16.6, ‘The molecular basis of mutation’ You might enjoy the Essay (p358), ‘Antibiotics that poison the ribosome,’ but the material will not be covered in this lecture.
3	NATURE & NURTURE Individuals do not exist outside of the context of genetic information nor do they exist outside of the context of use of materials and energy from the environment. Therefore, neither nature nor nurture are possible without the other. Both are always present for all individuals.
4	Changing appearance and behavior People have been trying to change their appearance for as far back as history goes (masks, body paint, ornamentation). Parents manipulate children with rewards and punishment. Education attempts to get individuals to adopt procedures and values that enable one to do old (culture) and new things.
5	Eugenics Scientific discoveries often move rapidly into common culture, Ideas about evolution and genetics were developed into the idea of eugenics, The basic idea of eugenics is to increase the rate of reproduction of ‘good’ people and decrease that of ‘defective’ people.
6	American Eugenics Was important early in 20^th century Lead to restrictive immigration policies Lead to enforce sterilization of individuals in mental institutions Was never based on solid science Feel into disfavor for a variety of reasons, including association with Hitler and the holocaust.
7	Are we mostly nature or mostly nurture? When we ask, ‘can a new environment can change an individual?’, we have to think about how long we are willing to wait to see change. Traits may respond to environmental conditions, but only at a specific time or stage of life. Childhood protein deficiency
8	Growth in a common (the same) environment If one finds differences between individuals growing in nature, the cause could be their environment or their genes. If one grows progeny from the different individuals together in the same environment and the differences persist, genetic factors are inferred to be the reason for the original difference.
9	The environment can be changed We generally think of nurture as something we can change, and genes as something we are stuck with. Doctors are trying to manipulate genes, but so far these efforts have not been successful. The ‘environment’ has many features or ‘states’. It is difficult to measure the limits of change and what ‘states’ are really different.
10	How do genes change? Genes change. The process of altering the information of a gene(s) is called mutation. Existing genes function, therefore we expect most genetic alterations to be: Deleterious (=harmful) Recessive (as function is maintain by non-transformed allele from other parent)
11	Mutation, Modifications of Genetic Information Quality (=sequence) of the information. Point mutations Insertions and deletions Quantity of the information Aneuploidy (addition of or subtraction of whole chromosomes) Duplication of parts of chromosomes
12	Human Genetic Polymorphisms Non-disease examples Taster versus Non-taster (p 1065) There is a compound, PTC, that some people can taste and other people can not taste. Some differences in preferences for food are likely based on experiences and others on innate biochemical (=genetic) differences among individuals. The RH blood types; + & -
13	Human Genetic Polymorphisms Disease examples There are a wide variety of genetic variants that result in conditions we recognize as diseases. The family pedigree is an important tool in deciding if a disease condition is due to genetics (because controlled crosses that produced a child for research are regarded as unethical).
14	Sickle Cell Anemia The disease: Episodes with enough intensity to cause death. Manifest as irregular shape of the red blood cells. Cause traced to a difference in the beta chain of hemoglobin. Sickle cell trait protects against malaria.
15	Sickle Cell Genetics Change in the 17^th base pair from T:A to A:T causes 6^th amino acid of the beta chain of hemoglobin to change from glutamic acid to valine. Though only one out of 147 amino acids is different the hemoglobin now has a tendency to crystallize and change the shape of the red blood cell.
16	Whole Chromosome Changes Most individuals with an extra or missing chromosome die shortly after fertilization. Extra chromosome 21 individuals survive to birth and are known as Down syndrome. Incidence increases with age of mother. Aneuploidy of sex chromosomes is tolerated by cells because only one of the two X chromosomes in females is active.
17	X & Y Chromosomal Anomalies XX & XY are the normal female and male. O symbol is used for absence of chromosome. XO = Turner syndrome XXY = Klinefelter syndrome Neither of the above individuals is fertile. XYY = These individuals are fertile and can not be distinguished phenotypically from XY males.
18	Sex Linked Genetic Traits Color Blindness Test figures are used to ‘score’ individual The recessive allele resulting in color blindness (cb) is on the X chromosome. If males have the cb allele, they are COLOR BLIND. Females have to be homozygous cb cb to be COLOR BLIND.
19	Genes and Behavior Allelic differences can be associated with behavioral differences. Often different genes don’t determine specific behaviors,but rather the probability of a behavior or event. Genes effect the likelihood of diseases such as cancer.
20	PEDIGREES
21	PEDIGREES
22	MAPPING THE HUMAN GENOME
23	INDIVIDUALITY There are many (30,000) loci in our DNA. Even though every person is identical for far over half our genes, many loci do vary and each individual is genetically unique (distinguishable from other individuals). This is the situation for almost all biparentally reproducing organisms.
24	FORENSIC GENETICS Polymerase Chain Reaction Is based on repeated amplification of minute amounts of DNA. Provides the basis for saying evidence is compatible with guilt or establishing that an alleged perpetrator could NOT be the source of the DNA. Because we can reject hypotheses with certainty, genetic evidence is most useful to establish innocence.
25	Problem If each of 10 loci had two alleles (and therefore 3 genotypes per locus) there would be 3¹⁰ = 59,049 different possible genotypes. How many different genotypes would be possible if each of the ten loci had 3 alleles?
26	Vocabulary aneuploid deleterious Down syndrome eugenics forensic genetics mutation Nature = genes Nurture = environment pedigree point mutation sex linked traits sickle cell anemia