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80 Cards in this Set
- Front
- Back
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What is a dihybrid cross?
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when two sets of alleles are crossed.
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What does Mendel's Independent Assortment state?
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that chromosomes act independently of each other
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How do you figure out how many different kinds of gametes there are?
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need to know different # gametes = 2^n. "n" is the number of DIFFERENT allele pairs.
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What is polygenic inheritance? What is an example?
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When a single trait is affected by many genes. an example is height in humans
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What is pleiotrophy? What is an example of this?
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When one gene affects many traits. Kartaganer's Syndrome (reversed organs, sterility and hearing loss. all from one incorrect gene)
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What is independent assortment?
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What one pair of chromosomes does has NO impact on other chromosomes
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What is incomplete dominance?
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When two different color plants are crossed and their offspring are a different color than the parents
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What is penetrance? What is an example?
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the proportion of individuals who show the phenotype that is expected from their genotype. Tay-Sach's disease
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What is expressivity? What is a disease that shows it?
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The degree of penetrance shown. Ectrodactyly "lobster claw hands"
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What modifies the genotype to give the final phenotype?
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the environment
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What is epistasis? What can be caused by another nonallelic gene?
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expression of genes can be modified by other genes. the modification of the expression of one gene can be caused by another nonallelic gene.
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What does genome mean?
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all of your genes
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What is sex determined by?
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sex chromosomes.
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What are autosomes?
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non-sex chromosomes
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What does homogametic mean?
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that all of the eggs that are formed will be the same.
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What does heterogametic mean?
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that all of the sperm that are formed will be different.
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Who determines the sex of a child?
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males
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What are sex linked characteristics?
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traits which are present on the X chromosome but absent on the Y chromosome
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What is the Lyon Hypothesis? What is another name for it?
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dosage compensation. a Barr body is a black spot in the nucleus of a cell, which is an inactivated X chromosome. It is inactivated so females (like men) only have one X chromosome so other X chromo. doesn't overmanufacture genes
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What is an example of dosage compensation?
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some heterozygous females have some areas on the body that can't perspire
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Where are sex-influenced genes located? What are they? What are they controlled by?
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on the autosomes. They are genes that are expressed to a greater or lesser extent and they are controlled by they sex of the person
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What are linked genes?
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genes that are on the same chromosome
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What are two different types of mutations?
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1. gene mutations
2. chromosomal abrrations |
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What could a change in the number of chromosomes be? What is it? What is an example?
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aneuploidy. When there is a change in the number of chromosomes by less than a hapoid set. Down Syndrome (have an extra #21 chromo)
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What is polyploidy? What is it common in?
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An increase in the number of chromosomes by a complete haploid set. Common in plants
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What is deletion?
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When a gene breaks off from a chromosome
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What is duplication?
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a gene added to a chromosome
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What is translocation?
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when a gene breaks off from a chromosome and attaches to a completely different chromosome
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What is inversion?
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When a gene on the end of a chromosome goes to the top of the chromosome (switched location)
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What is pedigree analysis? Does a dominant trait ever skip a generation? What about a recessive trait?
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how people can trace genetic diseases. nope. They commonly do.
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What are genetic lethal drugs mostly inherited as? What's an example?
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homozygous recessive. (This is why marriages are banned for close relatives) Cystic fibrosis
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What is evolution?
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a change in the population of organisms with time
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What is natural selection? Who came up with it? What is another name?
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the interaction between the environment and the phenotype of the organism. Darwin. Descent with modification.
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What are the ideas of natural selection? (4)
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1. like begits like
2. Within any population, variations exist. Some are inheritable. 3. # of individuals who survive and reproduce is small compared to the # born 4. reproductive success is determined by variations the individuals inherit |
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What are the five factors that suggest that evolution exists?
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1. biogeography (Tasmanian wolf)
2. Fossil record. (Law of Superposition, transitional fossil, chicken with teeth) 3. Comparative anatomy (homologous, analogous, vestigial structures) 4. DNA and proteins 5. Similar early pattern of embroyic development (fish, reptiles, birds, humans) |
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What is the synthetic theory of evolution based on?
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population genetics.
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What is a population?
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an interbreeding group of organisms
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What is a gene pool?
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the total of all the alleles of all the genes of all the individuals in a population
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What 5 things does the Hardy-Weinburg Law state?
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1. Matings occur at random
2. All alleles are equally viable 3. no entry or exit of alleles 4. no mutations 5. must have a large population |
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What does the Hardy-Weinburg Law state?
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that the population will not change and remain genetically the same if the criteria are followed
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What is the Law of Superposition?
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the bottom layer of a fossil mountain has the oldest fossils and the top layer has the newest fossils
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What are homologous structures?
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When two organisms have a structure that has a common orgin but not necessiarly a common function
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What are analogous structures?
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They have the same function but a different evolutionary background
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What are vestigial structures?
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structures that no longer have a use
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What are the 5 agents of evolution?
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1. mutations
2. gene flow 3. genetic drift 4. natural selection 5. non-random mating |
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What are mutations? What does it introduce?
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a change in the DNA of a gene. a variation into a population
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What is gene flow?
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a migration of organisms
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What is immigration?
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It increases genetic diversity (more genes... ??)
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What is emigration?
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decreases genetic diverstiy. population (genes) leaving population
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What is non-random mating in plants and animals?
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plants: self-fertilization
animals: inbreeding |
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What happens to the allelic frequency in animals during inbreeding? What occurs more frequently?
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the allelic frequency
homozygous conditions |
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What does inbreeding depression mean?
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that since there is an increase in homozygous conditions there is also an increase of genetic diseases.
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What is genetic drift?
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a change in the allelic frequency of a small popluation as a result of chance
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What are two types of genetic drift?
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1. population bottleneck
2. founder effect |
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What is population bottleneck?
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When there is a drastic change in the number of population by an event that has little or nothing to do with natural selection (elephant sea bulls and cows)
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What is the founder effect?
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When a small group breaks off from a larger population, goes some distance, and founds their own population (Amish)
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What is consaguinity?
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When a population has a high degree of blood relationships
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Natural selection is the interaction between phenotypes and what else? What is the result of natural selection?
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environment
adaptation |
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What is stabilizing selection?
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When continual stresses select against extreme phenotypes making the population more uniform
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What is disruptive selection?
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When environment changes select for the two extreme phenotypes and not making the population uniform
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What is directional selection?
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When environmental changes go in one direction, favoring phenotypes at one extreme and causing the normal distribution to shift
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What are the four ways to re-establish genetic diversity in a population?
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1. mutation
2. immigration 3. recombination (crossing over) 4. heterozygote superority (Hh being the superior genotype b/c it allows for both H and h) |
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Creating genetic diversity can offset natural selection by: (3)
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1. mutations
2. recombination 3. immigration |
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Sometimes natural selection will maintain diversity by: (2)
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1. heterozygote superority
2. frequency dependent selection |
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What does heterozygote superority mean?
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that the heterozygous genotype would be dominate over the homozygour recessive and dominant.
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What is frequency dependent selection?
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the fitness of a particulat genotype is inversely proportional to its frequency in the population. (3 color water bug)
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What is species defined as?
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a group of interbreeding organisms that are reproductively isolated from other groups. Each species has a latin name
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What is allopatric speciation?
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when new a new species is made by geographic separation. (see Founder Effect here) squrrels in the north
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What is a race?
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a local population that is inside a bigger population with some differences.
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What is sympatric speciation? What does it usually form?
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when a new species is created but it doesn't require geographic isolation. a hybrid (mule)
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Matintaining genetic isolation is done by these isolation mechanisms: (2)
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1. prezygotic barriers
2. postzygotic barriers |
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What are prezygotic barriers: (6)
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1. ecological isolation
2. behavorial isolation 3. temporal isolation 4. gametic isolation 5. sperm can't survive in female's uterus 6. genetalia isn't compatible |
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What are postzygotic barriers? (4)
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1. zygote doesn't develop
2. hybrid inviability 3. hybrid sterility 4. hybrid breakdown |
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What happens in ecological isolation?
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When the ecological differences keep two similar species apart
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What happens in behavorial isolation?
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different mating habits keep closely related species apart
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What happens in temporal isolation?
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different species have only certain times during the year or day when they can breed
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What happens in gametic isolation?
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When the egg and sperm don't fuse together
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What happens in hybrid inviability?
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When the fetus is spontaneously aborted
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What happens in hybrid sterrility?
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When a hybrid is born but is sterile
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What happens in hybrid breakdown?
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when a hybrid is born and fertile. Then the hybrid reproduces and the 2nd generation is either sterile or very weak
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