BESC1110 Lecture Notes - Lecture 3: Complications Of Pregnancy, Zygosity, Thalidomide
6 Jun 2018
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Conception to Birth: Lecture 3 Chapter 3
To understand:
• Genetic inheritance and the transmission of genetic differences
• Influence of genetics and environment
• Prenatal development and risks
• The birth process
Mechanisms of genetic transmission
• Gametes – sperm, ova
• Genes
• Chromosomes
Meiosis
Mitosis
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Genotype and phenotype
• Genotype
– Set of inherited traits
– Inborn capacity or potential
• Phenotype
– Traits as displayed or expressed
– Combination of genotype and modifying experiences
Genetic expression
• Dominant genes
– Always expressed in phenotype
– e.g., row eyes, urly hair, faial diples, type A lood, Hutigto’s
disease
• Recessive genes
– Must be paired with another recessive gene to be expressed
– e.g., blue eyes, colour-blindness, baldness, type O blood, PKU
Genetic variation
• Alleles
– Alternate genetic forms
• Homozygous
– Alleles for particular trait are identical
• Heterozygous
– Alleles for particular trait are different
• Co-dominance
– Both alleles expressed
• Polygenic traits
– Affected by many genes and environment
Genetic transmission of eye colour
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Influence of genetics and environment: genetic inheritance and the transmission of genetic differences, prenatal development and risks, the birth process. Mechanisms of genetic transmission: gametes sperm, ova, genes, chromosomes. E. g. , (cid:271)row(cid:374) eyes, (cid:272)urly hair, fa(cid:272)ial di(cid:373)ples, type a (cid:271)lood, hu(cid:374)ti(cid:374)gto(cid:374)"s disease: recessive genes. Must be paired with another recessive gene to be expressed. E. g. , blue eyes, colour-blindness, baldness, type o blood, pku. Genetic variation: alleles, homozygous, heterozygous, co-dominance, polygenic traits. E. g. down syndrome: dominant gene disorders. E. g. hu(cid:374)ti(cid:374)gto(cid:374)"s disease: recessive gene disorders. Optimal phenotypical expression of genotype depends on environment. Nature/nurture interaction: range of reaction, adoption studies, twin studies. Stages of prenatal development: conception, germinal (0 - 2 weeks) Blastocyst implants in uterus wall: embryonic (3 - 8 weeks) Decisions and issues: genetic counselling, prenatal diagnostics and genetic testing, genetic engineering, technological alternatives to natural conception, contraception, abortion. Prenatal influences: teratogens, critical or sensitive period, biogenic vulnerability of mother and baby. Prenatal hazards: medications, non-medicinal drugs, maternal disease, environmental hazards.
