BIOL 103 Chapter Notes -Assortative Mating, Gene Flow, Inbreeding Depression

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purplemammoth851

27 Sep 2013

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Population genetics: the study of genes and genotypes in a population. All the genes in a population make up its gene pool where each member of a population receives its genes from its parents which are members of the gene pool. A population is a group of interbreeding individuals. Large mountain or geographic barrier may separate two or more populations on the same continent. Populations are dynamic: change from one generation to the next in number, location, and genetic composition. Polymorphism: phenomenon that many traits display variation in phenotypes i. e. colour and pattern. o o. In elder-flowered orchid, both yellow- and red-flowered individuals are prevalent. Caused by 2 or more alleles that influence the phenotype of the individual. Polymorphic gene: gene that commonly exists as two or more alleles in a population. Monomorphic gene: exist as a single allele in a population.

Related Questions

1. Humans and chimpanzees share several polymorphic loci. Which is the LEAST plausible explanation for this fact?

A. Balancing selection has maintained polymorphism in both species

B. Incomplete lineage sorting left polymorphic loci and those have persisted since the speciation event.

C. Interbreeding has allowed introgression of alleles at theses loci in both directions.

D. Genetic variation provided by the polymorphic alleles enhances resistance to pathogens.

2. According to the social brain hypothesis, we should expect primates living in larger social groups to have:

A. Larger brains, specifically, a neocortex of relatively larger size

B. Lager incisors and canines, to defend against more social competitors

C. Smaller brains, because many individuals can work together to solve problems

D. Great variation in brain and neocortex size, with the dominant individuals having the largest

3. You extract DNA from human bones in an ancient village buried by volcanic ash. You discover that there is an extremely high frequency of the LCT allele for lactase persistence. What might you reasonably conclude about the population?

A. This population is likely the source of the high frequency of the LCT gene in Northern Europe

B. The village could not be more than 4,500 years old

C. The members of this population likely used domesticated livestock for their milk

D. villagers had a diet rich in wheat or another domesticated crop

4. Why do populations father from Africa have more deleterious mutations in their genome?

A. Repeated bottlenecks and founder effects made drift more intense more often

B. Populations farther from Africa have been exposed to more mutagens in the environment

C. As people migrated over the globe they interbred with Neanderthals and Denisovans

D. The populations are younger, so purifying selection has not had time to purge delirious mutations from the populations.

yelloweel732

___1. Nationally, the most common cause of Down Syndrome is
a. nondisjunction of Chromosome 21 during meiosis
b. translocation of Chromosome 21 onto another chromosome
c. inversion of a large section of Chromosome 21
d. deletion of the Down Syndrome gene
___2. In humans, sex is determined by
a. The presence or absence of the Y chromosome
b. The ratio of X chromosomes to sets of autosomes
c. The temperature during fetal development
d. Which parent is stronger at the time of conception
___3. A translocation is
a. a chromosomal abnormality in which a piece of one chromosome breaks off and attaches to a different chromosome
b. an abnormality in which the chromosomes are translocated out of the nucleus
c. a condition in which the chromosome has broken in two places and come back together with the middle segment backward
d. an abnormality in which there is an extra copy of one chromosome
___ 4. In snapdragons, a red-flowered plant crossed with a white-flowered plant produces all pink-flowered offspring. But crossing two pink-flowered plants produces red, pink, and white in a 1:2:1 ratio. This is a good example of
a. Incomplete dominance
b. Dominance of the red allele over the white allele
c. Lethal effects of the pink allele
d. Sex-linkage of the flower-color alleles
___ 5. If a person with type AB blood marries a person with Type O blood, what blood types are possible in their children? (Assume this trait is a single-gene trait, not complicated by interaction with other genes).
a. A, B, AB, or O
b. A or B only
c. AB or O only
d. AB only 2
___6. In what phase of meiosis are haploid nuclei first formed? a. Anaphase I b. Metaphase II c. Telophase II d. Metaphase I e. Telophase I
___7. What is the phenotype of a heterozygous tall pea plant? a. tall b. Tt c. TT d. tt e. dominant
___ 8. If genes A and B are far apart on a chromosome, and A and C are close together, which of the following observations is expected?
a. Crossing over will occur more often between A and C than between A and B
b. Crossing over will occur at equal frequencies between A and C, and between A and B
c. Crossing over will occur more often between A and B than between A and C
___9. Sometimes an organismâs genotype for one gene masks the effect of a different gene. This phenomenon is called
a. Dominance
b. Incomplete dominance
c. Co-dominance
d. Epistasis
e. Variable expressivity
___10. The dominant allele of a gene is
a. The one that is expressed most often in a population
b. The one that is expressed most often in any particular cross
c. The one that is expressed in an individual that has two different alleles
d. The one that is most healthy to have, that gives the greatest fitness
___11. In human cells, DNA replication occurs
a. In S phase of interphase
b. In G1 phase of interphase
c. In G2 phase of interphase
d. In prophase of mitosis
e. Whenever the cell needs to read the DNA to make proteins
___ 12. A process in which recipient cells take up genes from DNA molecules floating free in the surrounding medium is called
a. conjugation
b. specialized transduction
c. generalized transduction
d. transformation 3
___ 13. Most calico cats are female. However, a few rare males are observed. What is the genotype of a male calico cat?
a. X BX 0
b. X OY
c. X BY
d. X BYY
e. X BX OY
___ 14. A type of red-green color-blindness is a sex-linked (X-linked) recessive trait in humans. Can a woman have this type of color-blindness?
a. Yes, a woman could be color-blind if her mother and father were both heterozygous.
b. Yes, a woman could be color-blind but only if she has an abnormal number of sex chromosomes.
c. No, women can't show sex-linked traits because they lack a Y chromosome.
d. No, women can't show sex-linked traits because they have two X chromosomes.
e. Yes, a woman could be color-blind if her father was color-blind and her mother was a carrier (heterozygous).

BIOL 103 Chapter Notes -Assortative Mating, Gene Flow, Inbreeding Depression

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