H_D 101 1nd Edition Lecture 6 Outline of Last Lecture II. Introduction to Genetics and ChromosomesIII. DefinitionA. GenotypeB. PhenotypeC. ChromosomesD. GenesE. DNAF. AllelesG. MitosisH. MeiosisI. AutosomesJ. GametesOutline of Current Lecture IV. What is GeneticsV. Physical Appearance vs. Genetic MakeupVI. Reproductive InformationVII. Genetic CounselingVIII. Prenatal Diagnostic MethodsCurrent Lecture- What is Genetics:o A branch of biology that studies heredity.o Offspring resemble their parents because they inherit genes form their parents.o Genes are a set of instructions.o Genes are made of DNA that form chromosomes.o A typical human body has 46 chromosomes.o Each chromosomes has a twin.o You inherit one from your mom and the other from your dad.o The two matching chromosomes are called homologous chromosomes.o Homo – same logos – shape.o Each homologous chromosomes carries the same sequence of genes controlling the same inherited characteristics.o Many traits have two alternating gene forms we call alleles.o Sometimes one allele masks the expression of the other allele.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o The allele that covers the other is the dominant, and the one that is covered is the recessive.- Physical Appearance vs. Genetic Makeup:o An observable trait is the phenotype of an organism.o The genetic makeup or combination of alleles is called the genotype.o An organism genotypes codes for its phenotype.o If you inherit two of the same alleles from your parents you are said to be homozygous for the trait, pure-bred.o If you inherit two different alleles for the trait you are said to be heterozygous, hybrid.o Understand genes and the role of chromosome in inheritance is essential to the study of genetics.- Reproductive Information:o Genetic counseling.o Genetic testing.o Prenatal diagnosis and fetal medicine.- Genetic Counseling:o Have a child with serious defect.o Family history.o Same ethnic group – especially blood relative (first/second cousins).o Women at age 35+; men at age 40+o Women- serious infection early in pregnancy, x-rays early in pregnancy, stillbirth, death of newborn, miscarriage.o Helps couples. Assess chances of hereditary disorders. Choose best course of action.- Risks.- Family goals.o Recommended when. Couples has had difficulties, Aware of genetic problems. Woman is over 35.- Prenatal diagnostic methods:o Amniocentesis.o Chronic villus sampling.o Fetoscopy.o Ultrasound.o Maternal blood analysis.o Pre-implantation genetic
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