Genetics and Prenatal Development

1. 2 Genetics and Prenatal Development

2. L.O. 2.1 Genetic BasicsBuilding Blocks of Life • Chromosomes • DNA • Genes • Genomes

3. L.O. 2.1 Genetic BasicsExpression of Traits • Genotype-The totality of an individual’s genes • Phenotype-Actual Characteristics • This is what is seen or observed and can include a wide range of things

4. L.O. 2.1 Genetic BasicsExpression of Traits • Dominant Genes-Expressed characteristics • Recessive Genes-Not expressed, although it is a part of the genotype (genetic background) • Allele-Alternate form of a gene • Dominant-Recessive Inheritance

5. L.O. 2.1 Genetic BasicsExpression of Traits • Incomplete Dominance • Phenotype influenced primarily but not exclusively by the dominant gene • Polygenic Inheritance • Interaction of multiple genes

6. L.O. 2.2 Genetic BasicsThe Sex Chromosomes • The 23rd chromosomes pair determine male or female • Males more vulnerable to X-linked recessive disorders

7. L.O. 2.3 Genetic BasicsGenes and Environment • Behavior Genetics • Estimating influence of genes and environment on development • Utilize twins to understand importance of genetics and tease out environment effects

8. L.O. 2.3 Genetic BasicsGenes and Environment • Heritability • An estimate of the extent to which genes are responsible for differences among persons within a specific population • Concordance Rates • Percentage that indicates degree of similarity in phenotype among pairs of family members

9. The Human ExperienceConception and Prenatal Development

10. L.O. 2.7 The Beginning of LifeConception • For conception to occur there must be a released ovum and a sperm. • Ovulation releases the ovum, and if sperm available, fertilization can occur.

11. L.O. 2.8 The Germinal PeriodFirst 2 Weeks of Life • During the travel from the fallopian tube to the uterus cell division is taking place • Blastocyst • Trophoblast • Embryonic disk

12. L.O. 2.9 The Embryonic PeriodWeek 3-Week 8 • Key Developments • Embryonic Layers • Ectoderm • Mesoderm • Endoderm

13. L.O. 2.9 The Embryonic PeriodWeek 3-Week 8 • Key organs and structures are forming including • Heartbeat • Eyes, nose and mouth • Bone development • Arm and leg buds • Digestive system

14. L.O. 2.10 The Fetal PeriodWeek 9-Birth • The longest period of prenatal development • Heartbeat can be heard • Movement can be felt • Responds to sounds • Main impediment to viability is lung development

15. L.O. 2.11 Prenatal CareTraditional Cultures and Beliefs • Prenatal beliefs are impacted by generational wisdom of the time • These beliefs can include • Avoiding wine • Specific types of meat • Certain types of hot, cold food • Witches • Strong foods

16. L.O. 2.11 Prenatal CareScience Driven Prenatal Care • Some current science-driven prenatal methods are derived from traditional cultures which includes massages • Current care can vary by ethnicity and SES • Developing world less likely to receive prenatal care • Current focus on diet, exercise, and teratogens

17. L.O. 2.12 Prenatal CareDiet • Two key vitamins are iodine and iron • Iodine deficiency tends to be a bigger issue in developing countries • Iron is necessary for a healthy pregnancy

18. L.O. 2.12 Prenatal CareExercise • Continued physical activity is encouraged during pregnancy • Aerobic exercise encourages good cardiovascular health and positively benefits the fetus • A Non-aerobic exercise called Kegel exercises are also encouraged

19. L.O. 2.14 Prenatal CareTeratogens • Teratogens are environmental and bodily conditions that could be harmful • They can include tobacco, alcohol, prescription medications and other drugs • The physical environment could also be a teratogen due to malnutrition or exposure to hazardous chemicals

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21. Pregnancy Problems

22. L.O. 2.13 Chromosomal Disorders • Chromosomal disorders can occur because of an issue during meiosis • This may cause too many or too few chromosomes in the cells of the zygote • Two types of chromosomal disorders are: • Sex chromosome disorders • Disorder on the 21st chromosome (Down Syndrome)

23. L.O. 2.13 Sex Chromosome Disorders • Sex chromosomal disorder can result from extra X, an extra Y, or only an X and no second chromosome • Common consequences of sex chromosome disorders include: • Cognitive Deficit • Abnormality in reproductive system at puberty

24. L.O. 2.13 Down SyndromeTrisomy 21 • Identifiable by physical characteristics • Cognitive Deficits • Speech problems • Mental retardation • Social development varies • Lower life expectancy

25. L.O. 2.13 Parental Age and Chromosomal Disorder • Chromosomal disorders tend to NOT be passed from parent to child • Relationship between maternal age and chromosomal disorders • There may be a relationship between a father’s age and chromosomal disorders but it isn’t as clear

26. L.O. 2.14 TeratogensTiming of Teratogens • Teratogens can impact the developing fetus and embryo at any time • There does appear to be a critical period of prenatal development centered in the embryonic period