Lecture 3 recording:
• For disorders – you are not gonna to ask to list them and symptoms, they will be in a
Multiple choice section!!
• Know heading in textbook and not
• KNOW HEADINGS
• Pay attention
We all started out as single cell organisms – the single cell contains all of genetic info needed for
body to develop!!
• Proteins are workers of the body
• Genes are short segments of DNA
• Scientists have been able to ID most genes in human genome!!
• Nucleus of each cell contains chromosomes
• Chromosomes are rod-like structure made up of DNA
• Genes are short segment of DNA
• DNA are double stranded molecules
• DNAcan replicate itself – Mitosis!!!
• Genes effect everything – but they don’t determine anything!!
Genotypes and Phenotypes
• Genotype = refers to the genetic material of the individual
• Phenotype = refers to the apparent, observable, measurable
characteristics of the individual. Meiosis: (Sexual Reproduction) Mitosis:
• Cell division resulting cell is identical
• Form of cell division in which to the parent cell
Chromosomes split, • duplication and breaking part
• Each member has 23 chromosomes
• Resulting cell is NOT identical to
• Crossing over – exchange of genetic
material b/w chromosomes –this results
• Crossing over and extra division when
compared to mitosis!!
Some genes are universal,
Alleles: different forms of gene that occupy a particular LOCUS on the chromosome!!
e.g. alleles for eye color
Dominant: either one or two dominant allele(s) result in expression
Tongue curling -- dominant trait!! Recessive: has to be two recessive allele result in expression.
Polygenetic inheritance: phenotype is influenced by many gens (i.e. height)
Regulation genes: turn other genes on or off!!
• i.e development of jaw – the regulator gene turns of sooner in chimpanzees
METHODS OF STUDYING HEREDITARY INFLUENCES
Selective breeding: rats make their way through maze to get a reward, if you mate braze
bright with other maze bright -- the variation deepens
Behaviour genetisisits use twin or adoption study:
Identical twins: comes from same single cell, same genetic info
Fraternal twins: 50%, like any other type of siblings
Adoption studies: looks at contributions of environment VS genetics!!
Canalization: some traits have restrictions that follow genetic trait
i.e. all children speak and walk around 1 year of age!!
* body has a certain plan for certain traits, so it is very difficult for environment to change it
Response to stress and number of stress events
• the number of stressful events depends on environment
Mutations: could be spontaneous or due to environment
• could be beneficial or harmful • mutations is inherited ONLY if it is present within the sex cells!!
Founder effect: small group of people from a larger population start a new population of their
• Usher syndrome in Louisiana!!! -- children are born blind!!
• In small population, it is more likely to get recessive alleles
Reaction range: variability of expression is influenced by environmental factors
• E.g: Intellectual problems
Gene-environment correlation: impact of genotype on environment
1. Passive Gene-environment correlation: parents provide the genes also provide env
• Its passive because the children are not doing anything to choose the env, the parents
2. Evocative Gene-env: genotype elicits particular response
• Something that baby is doing is eliciting a response
3. Active-gene env: the child selects contexts that they find rewarding, child actively seek
to certain environments that will strengthen their traits
• For older children
2 million Ova in ovaries Sperm produced in testicles
Ovum is released every 28 days 2 million per day
46- meiosis – 23 chromosomes Each ind sperm cell has 23 chr
Swept along Fallopian tubes Sperm from father penetrates ovum form mom – zygote!!
Zona Palucida: gelatinous layer
• As soon as 1 sperm cell penetrates – no other sperm can get inside!!
• Menstration: Ovum is expelled and sperm is absorbed by WBC
X chromosome is larger then Y, Y chromosome swims faster
Chareotype: a photograph of all the chromosomes in a cell!!
1. Monozygotic twins (identical): single ovum splits (100% identical)
2. Dizygotic twins (Fraternal twins): ovary releases two ova
• Same genetic relationship as any other sibling (50%
• It could happen near the end of women’s reproductive cycle
Infertility: inability to conceive after 12-18 months of trying
Why infertility happens?: 1. egg quality decreases over time 2. inflammation or scarring due
1. Artificial insemination: inserting sperm into uterus
2. In vitro fertilization: egg fertilized with sperm outside and transferred to Uterus
3. Gamete intrafallopian transfer: Egg & sperm combine and placed unfertilized into
4. Zygote intrafallopian transfer: egg fertilized with sperm and zygote transfer 5. Introcytoplasmic sperm injection: single sperm is injected into the egg
Stages of Prenatal development:
Germinal stage (0-2 weeks):
• When egg is entering fallopian tube and implants uterus
• At 8 cell mark – there’s differentiation
• Blastocyst: ball of cells
• Differention happens: blastocyst divides into two things
• 1. Embryonic disk: developing organism
• 2. Trop