Genetics
Vocabulary (Chapter 14): character, trait, true-breeding, homozygous, heterozygous, hybridization, Law of Segregation, alleles, dominant, recessive, Punnett square, phenotype, genotype, testcross, monohybrid cross, dihybrid cross, Law of Independent Assortment, complete dominance, incomplete dominance, codominance, Tay-Sachs disease, pleiotropy, epistasis, multiple alleles, polygenic inheritance, quantitative characters, multifactorial characters, pedigree, carriers, albinism, cystic fibrosis, sickle-cell disease, Huntington's disease, achondroplasia, amniocentesis, chorionic villus sampling (CVS)
Objectives:
After attending lectures and studying the chapter, the student should be able to:
1. Define diploid and state which cells in your body are diploid.
2. State the number of chromosomes in your diploid cells and state how many of those
chromosomes came from your father and how many came from your mother.
3. Distinguish between autosomes and sex chromosomes, state how many of each are in
your diploid cells, and state the sex-chromosome combinations that are in human males
and human females.
4. Describe an individual's karyotype.
5. Explain the relationship between genes and chromosomes.
6. Explain the relationship between genes and alleles.
7. Describe linked genes.
8. State the number of alleles you have for each gene in your diploid cells and state how
many of those alleles came from your father and how many came from your mother.
9. Distinguish between an individual's phenotype and genotype.
10. Distinguish between autosomal traits and sex-linked traits.
11. Distinguish between complete dominance, incomplete dominance, and codominance.
12. Describe the multiple allele inheritance pattern of the human ABO blood type.
13. Describe and give an example of polygenic inheritance.
14. Describe and give an example of epistasis.
15. Describe and give an example of pleiotropy.
16. Describe a pedigree and use a pedigree chart to determine patterns of inheritance.
17. List the 4 steps used in genetics problems to determine offspring possibilities.
18. Use the 4-step genetics-problem-solving process to work single-gene cross and 2-gene
cross genetics problems, including monohybrid and dihybrid crosses.
19. Give examples of and work genetics problems relating to each of the following human
single-gene traits:
a. autosomal and sex-linked traits(chapter 15);
b. normal traits and genetic disorders;
c. traits with multiple alleles in the population;
d. recessively-inherited and dominantly-inherited traits; and,
e. traits with complete dominance, incomplete dominance, and codominance.
Vocabulary (chapter 15): sex-linked genes, duchene muscular dystrophy, hemophilia, Barr body, linked genes, nondisjunction, aneuploidy, monosomic, trisomic, polyploidy, deletion, duplication, inversion, translocation, Down syndrome, Turner syndrome, Klinefelter syndrome
20. Describe meiotic nondisjunction and explain how this can lead to human chromosomal
abnormalities.
21. Describe the human chromosomal abnormalities that lead to Down syndrome, Turner
syndrome, and Klinefelter syndrome.
22. Describe genomic imprinting and how it affects phenotypic expression of genes.
23. Understand linked genes and why they do not show the same pattern of inheritance as genes located on different chromosomes.
| 1101239129 | Character | An observable heritable feature that may vary among individuals. |  |
| 1101239130 | Trait | One of two or more detectable variants in a genetic character. | |
| 1101239131 | True-Breeding | Referring to organisms that produce offspring of the same variety over many generations of self-pollination. | |
| 1101239132 | hybridization | In genetics, the mating, or crossing, of two true-breeding varieties. | |
| 1101239133 | P Generation | The true-breeding (homozygous) parent individuals from which F1 hybrid offspring are derived in studies of inheritance; P stands for "parental." | |
| 1101239134 | F1 generation | The first filial, hybrid (heterozygous) offspring arising from a parental (P generation) cross. | |
| 1101239135 | F2 generation | The offspring resulting from interbreeding (or self-pollination) of the hybrid FF1 generation. | |
| 1101239136 | The Law of segregation | Mendel's first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation. |  |
| 1101239137 | Allele | Any of the alternative versions of a gene that may produce distinguishable phenotypic effects. |  |
| 1101239138 | Dominant Allele | An allele that is fully expressed in the phenotype of a heterozygote. | |
| 1101239139 | Recessive Allele | An allele whose phenotypic effect is not observed in a heterozygote. | |
| 1101239140 | Genotype | The genetic makeup, or set of alleles, of an organism. |  |
| 1101239141 | Phenotype | The EXPRESSED/observable physical and physiological traits of an organism, which are determined by its genetic makeup. | |
| 1101239142 | The Law of Segregation | Mendel's first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation. | |
| 1101239143 | Punnett Square | A diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype. |  |
| 1101239144 | Homozygous | Having two identical alleles for a given gene. |  |
| 1101239145 | Heterozygous | Having two different alleles for a given gene. |  |
| 1101239146 | Phenotype | Expressed. The observable physical and physiological traits of an organism, which are determined by its genetic makeup. |  |
| 1101239147 | Genotype | The genetic makeup, or set of alleles, of an organism. |  |
| 1101239148 | Testcross | Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring reveals the unknown genotype. |  |
| 1101239149 | The Law of Independent Assortment | Mendel's second law, stating that each pair of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes. | |
| 1101239150 | Monohybrids | An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aa. |  |
| 1101239151 | Monohybrid Cross | A cross between two organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant). |  |
| 1101239152 | Dihybrids | An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb. |  |
| 1101239153 | Dihybrid Cross | A cross between two organisms that are each heterozygous for both of the characters being followed (or the self-pollination of a plant that is heterozygous for both characters). |  |
| 1101239154 | The multiplication rule | A rule of probability stating that the probability of two or more independent events occurring together can be determined by multiplying their individual probabilities. | |
| 1101239155 | The addition rule | A rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities. | |
| 1101239156 | Complete dominance | The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable. | |
| 1101239157 | Incomplete dominance | The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele. |  |
| 1101239158 | Codominance | The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways. | |
| 1101239159 | Tay-Sachs Disease | A human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth, followed by death within a few years. | |
| 1101239160 | Pleiotropy | The ability of a single gene to have multiple effects. | |
| 1101239161 | Epistasis | A type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene. | |
| 1101239162 | Quantitative Characters | A heritable feature that varies continuously over a range rather than in an either-or fashion. | |
| 1101239163 | Polygenic Inheritance | An additive effect of two or more genes on a single phenotypic character. | |
| 1101239164 | Norm of Reaction | The range of phenotypes produced by a single genotype, due to environmental influences. | |
| 1101239165 | Multifactorial | Referring to a phenotypic character that is influenced by multiple genes and environmental factors | |
| 1101239166 | Pedigree | A diagram of a family tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over multiple generations. | |
| 1101239167 | Carriers | In genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder. The heterozygote is generally phenotypically normal for the disorder but can pass on the recessive allele to offspring. | |
| 1101239168 | Cystic Fibrosis | A human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by an excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated. | |
| 1101239169 | Sickle Cell Disease | A recessively inherited human blood disorder in which a single nucleotide change in the β-globin gene causes hemoglobin to aggregate, changing red blood cell shape and causing multiple symptoms in afflicted individuals. | |
| 1101239170 | Huntington's Disease | A human genetic disease caused by a dominant allele, characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after the onset of symptoms. | |
| 1101239171 | Amniocentesis | A technique associated with prenatal diagnosis in which amniotic fluid is obtained by aspiration from a needle inserted into the uterus. The fluid and the fetal cells it contains are analyzed to detect certain genetic and congenital defects in the fetus. |  |
| 1101239172 | Chorionic Villus Sampling (CVS) | A technique associated with prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital defects in the fetus. |  |
| 1101239173 | Chromosome Theory of Inheritance | A basic principle in biology stating that genes are located at specific positions (loci) on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns. | |
| 1101239174 | Wild Type | The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype. | |
| 1101239175 | Sex-Linked Gene | A gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome. | |
| 1101239176 | X-Linked Genes | A gene located on the X chromosome; such genes show a distinctive pattern of inheritance. | |
| 1101239177 | Duchenne Muscular Dystrophy | A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue. | |
| 1101239178 | Hemophilia | A human genetic disease caused by a sex-linked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury. | |
| 1101239179 | Barr Body | A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome. | |
| 1101239180 | Genetic Recombination | General term for the production of offspring with combinations of traits that differ from those found in either parent. | |
| 1101239181 | Parental Types | An offsprring with a phenotyp that matches one of the true-breeding parental (P generation) phenotypes; also refers to the phenotype itself. | |
| 1101239182 | Recombinant Types/Recombinants | An offspring whose phenotype differs from that of the true-breeding P generation parents; also refers to the phenotype itself. | |
| 1101239183 | Crossing Over | The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis. | |
| 1101239184 | Genetic Map | An ordered list of genetic loci (genes or other genetic markers) along a chromosome. | |
| 1101239185 | Linkage map | A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes. | |
| 1101239186 | Map Units | A unit of measurement of the distance between genes. One map unit is equivalent to a 1% recombination frequency. | |
| 1101239187 | Nondisjunction | An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other. | |
| 1101239188 | Aneuploidy | A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number. | |
| 1101239189 | Monosomic | Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two. | |
| 1101239190 | Trisomic | Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two. | |
| 1101239191 | Polyploidy | A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division. | |
| 1101239192 | Deletion | (1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene. | |
| 1101239193 | Duplication | An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such taht a portion of a chromosome is duplicated. | |
| 1101239194 | Inversion | An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated. | |
| 1101239195 | Translocation | (1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants. | |
| 1101239196 | Down Syndrome | A humaan genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and heart and other defects that are generally treatable or non-life threatening. | |
| 1101239197 | Genomic Imprinting | A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent. |
