CHAPTER 3 GENES, ENVIRONMENT AND DEVELOPMENT - PowerPoint PPT Presentation

View by Category
About This Presentation
Title:

CHAPTER 3 GENES, ENVIRONMENT AND DEVELOPMENT

Description:

chapter 3 genes, environment and development – PowerPoint PPT presentation

Number of Views:95
Avg rating:3.0/5.0
Slides: 38
Provided by: Suzanne258
Learn more at: http://mydsn.net
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: CHAPTER 3 GENES, ENVIRONMENT AND DEVELOPMENT


1
CHAPTER 3 GENES, ENVIRONMENT AND DEVELOPMENT
2
Learning Objective
  • What do evolution and species heredity contribute
    to our understanding of universal patterns of
    development?

3
Species Heredity
  • Genetic endowment
  • What species members have in common
  • Govern maturation and aging processes
  • Examples in humans
  • Two eyes, sexually mature at ages 12-14
  • Evolved through natural selection
  • Genes passed on which allow species to adapt

4
Evolution
  • Evolution Charles Darwin (1809-1882)
  • Specie characteristics change over time
  • New species can evolve from earlier ones
  • Main arguments
  • There is genetic variation in a species
  • Natural selection
  • Adaptive genes passed on more frequently

5
Kettlewells Moths
  • An interaction
  • Genetic variability (color of wings)
  • Adaptation to a specific environment (country
    vs.city)
  • Survival
  • Requires adaptation
  • Adaptation
  • Genetic variability

6
Modern Evolutionary Perspectives
  • What we do today was adaptive for our ancestors
  • Species heredity based on natural selection
  • Genetic make-up gradually changes
  • New or modified species arise
  • Cultural evolution based on learning
  • Better ways of adapting learned
  • Shared through language

7
Learning Objectives
  • What are the basic workings of individual
    heredity, including the contributions of genes,
    chromosomes, the zygote, and the processes of
    mitosis and meiosis?
  • Note the difference between genotype and
    phenotype.

8
Individual Heredity The Genetic Code
  • Zygote Union of sperm ovum at conception
  • Contains 23 pairs of chromosomes
  • One pair from each parent
  • Each pair influences a characteristic
  • Chromosomes thousands of genes containing DNA
  • Meiosis process producing sperm, ova
  • Mitosis cell-division process creating all other
    cells
  • Throughout life

9
The Human Genome Project
  • Massive genome analysis projects
  • 999/1000 human base chemicals identical
  • 1/1000 accounts for differences between us
  • Humans/Chimps share 96 genetic material
  • Gene variants evolved in recent centuries
  • Adaptations to food sources, diseases,etc.
  • Findings also useful to identify genes associated
    with disease, drug treatments

10
Genetic Uniqueness and Relatedness
  • ID twins zygote divides forms 2 individuals
  • 64 trillion genetically unique babies per any
    couple
  • 2 chromosomes in sperm or ovum
  • Males XY, Females XX
  • Parent/Child 50 related genetically
  • Siblings on average 50 related genetically
  • Fraternal twins 2 ova released, fertilized by 2
    sperm

11
Translation of the Genetic Code
  • Genotype genetic makeup a person inherits
  • Phenotype expressed traits of the person
  • Genes instructions for development
  • Characteristics like eye color
  • Regulator genes turn gene pairs on/off at
    different times
  • Turned on for adolescent growth spurt
  • Turned off in adulthood
  • Always influenced by environmental factors also

12
Learning Objectives
  • How are traits passed from parents to offspring?
  • What is an example of how a child could inherit a
    trait through each of the three mechanisms
    described in the text?

13
Mechanisms of Inheritance
  • Single gene-pair inheritance
  • Dominant gene dominant trait
  • Recessive genes
  • Trait expressed if paired with a similar gene
    (Homozygous)
  • Trait not expressed if paired with dissimilar
    gene (Heterozygous)
  • Recessive traits homozygous recessive
  • Dominant traits hetero or homozygous gene pair

14
Example Sickle-Cell Disease
  • About 9 affected in US
  • Homozygous recessive
  • Heterozygous are carriers
  • Can transmit gene to offspring
  • If both parents carriers 25 chance
  • Example of incomplete dominance
  • Offspring may have sickling episodes

15
(No Transcript)
16
Sex-Linked Inheritance
  • Single genes located on sex chromosomes
  • Actually X-linked
  • Males - no counterpart on Y chromosome
  • Only needs one to be color-blind
  • Females - counterpart on 2nd X chromosome
  • Usually for normal color-vision (dominant)
  • Must inherit on both to be color-blind
  • Also Hemophilia, Duchene MS, others

17
  • X-Linked Inheritance

18
Polygenic Inheritance
  • For most important human characteristics
  • Height, intelligence, temperament, etc.
  • Trait influenced by multiple pairs of genes
  • These traits are normally distributed
  • I.e., found in the same proportion in all
    populations

19
Learning Objectives
  • What methods are used to screen for genetic
    abnormalities?
  • What are the advantages and disadvantages of
    using such techniques to test for prenatal
    problems?
  • What are some abnormalities that can currently be
    detected with genetic screening?

20
Mutations
  • A change in gene structure/arrangement
  • Produces a new phenotype
  • More likely in sperm than in ova
  • May be harmful or beneficial
  • Can be inherited by offspring

21
Chromosomal Abnormalities
  • Errors in chromosome division during meiosis
  • Too many or too few chromosomes result
  • Most spontaneously aborted
  • Down Syndrome Trisomy 21
  • Physical characteristics
  • Mental retardation
  • Related to age of both parents
  • Often develop Alzheimers in middle age

22
  • The rate of Down syndrome births increases
    steeply as the mothers age increases.

23
Sex chromosome Abnormalities
  • Turners syndrome 1/3000 females
  • Single X chromosome small, unable to reproduce
  • Klinefelter syndrome 1/200 males
  • XXY Sterility, feminine traits
  • Fragile X syndrome one arm on X is fragile
  • Usually males (sex-linked inheritance)
  • Most common heredity cause of MR

24
Genetic Diagnosis and Counseling
  • Helps people understand and adapt
  • Prenatal diagnosis techniques include
  • Amniocentisis, preimplantation genetic diagnosis
  • Human genome project yielded much info
  • Eg., Huntingtons disease
  • Deterioration of nervous system
  • Single dominant gene
  • One affected parent 50 chance in offspring

25
Learning Objectives
  • How do scientists study the contributions of
    heredity and environment to behavioral
    characteristics?
  • Describe the logic of the methods, as well as
    strengths and weaknesses of each method
  • How can concordance rates help researchers
    estimate the influences of heredity and
    environment?
  • How do genes, shared environment, and nonshared
    environment contribute to individual differences
    in traits?

26
Behavioral Genetics
  • Genetic/environmental cause of traits
  • Heritibility estimates
  • Experimental and selective breeding
  • Tryons maze-bright rats
  • Twin, adoption, family studies
  • Reared together or apart
  • Concordance rates

27
(No Transcript)
28
Estimating Influences
  • Genetic similarity
  • Degree of trait similarity
  • Shared environmental influence
  • Living in the same home
  • Non-shared environmental influences
  • Unique experiences

29
Molecular Genetics
  • Analysis of genes and their effects
  • May compare humans with other animals
  • Eg. Alzheimers disease
  • Most common form of old age dementia
  • Twin studies show heritability
  • Possible genetic links being tested
  • Environmental factors also being tested
  • High cholesterol, head injury

30
Learning Objectives
  • How do genes and environments contribute to
    individual differences in intellectual abilities,
    personality and temperament, and psychological
    disorders?
  • What do researchers mean when they talk about the
    heritibility of traits?
  • Which traits are more strongly heritable than
    others?

31
IQ Accounting for Individual Differences
  • Correlations highest in identical twins
  • Genetic factors determine trait
  • Correlations higher if twins reared together
  • Environmental factors
  • Non-shared experiences influential
  • Identical twins more alike with age

32
(No Transcript)
33
Temperament Personality
  • Temperament Correlations
  • Identical twins .50 to .60
  • Fraternal twins 0 (even reared together!)
  • Personality Correlations Similar
  • Shared environment unimportant
  • Genetic inheritance important
  • Non-shared experiences important for differences

34
  • Correlations between the traits of identical
    twins raised apart in Minnesota Twin Study.

35
Psychological Disorders
  • Schizophrenia concordance rates
  • ID twins 48
  • Fraternal twins 17
  • Affected parent increases risk even if adopted at
    birth
  • Inherited predisposition
  • Environmental factors (triggers)
  • Prenatal exposure to infection suspected

36
Learning Objectives
  • What is an example that illustrates the concept
    of a gene-environment interaction?
  • What are three ways that genes and environments
    correlate to influence behavior?
  • What are the major controversies surrounding
    genetic research?

37
Gene-Environment Interactions
  • Based on correlations
  • Eg., Sociable genes
  • Passive interaction
  • Create social home environment
  • Evocative interaction
  • Smiley baby gets more social stimulation
  • Active interaction
  • Shy child seeks solitary activities
About PowerShow.com