BIOL 1001 Chapter : BIOL 1001 Chapter 12

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azuremammoth471

15 Mar 2019

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Document Summary

Many traits in humans are not controlled by one gene, but by many genes: eye color, height, hair color, etc. Several traits in humans that are controlled by one gene, makes it easy to determine you phenotype and possible your genotype. The presence or absence of these traits does not express anything meaningful. You are not a freak if you have/lack these traits. Example: earlobes: ee or ee was free/unattached phenotype (homozygous dominant or heterozygous, ee was attached phenotype (homozygous recessive) Many disease (>10,000) are due to single genes. People knew that sperm and eggs transmitted information about traits. Problem: would expect variation to disappear, variation in traits persists. Monk in a monastery in late 1800s. Experimentation with pea plant inheritance took place in the monastery garden. Found indirect but observable evidence of how parents transmit genes to offspring. Each has a specific location (locus) on a chromosome. Dominant allele masks a recessive allele that is paired with it.

Related Questions

Part A

In humans, individuals may or may not have a widowâs peak. This trait is controlled by genes at a single locus, with the allele for having a widowâs peak dominant to the allele for not having one. A population of humans is sampled; 59 have a widowâs peak and 44 do not. 25 of the people with a widowâs peak are homozygous dominant. What are the frequencies of the dominant and recessive alleles observed in this sample?

p = _____

q = _____

Part B

In a species of corn, individuals have either narrow or wide corn cobs. This trait is controlled by genes at a single locus, with the narrow cob allele dominant to the wide cob allele. A farmer counts 74 narrow cob and 113 wide cob plants in a field. Of the narrow cob plants, 28 are homozygous dominant. What are the frequencies of the dominant and recessive alleles observed in this sample?

p = _____

q = _____

Part C

In a population of peas, the frequency of the dominant allele for a purple flower is 0.61 and the frequency of the recessive allele for a white flower is 0.39. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 500 peas?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

Part D

In mice, a mahogany coat color allele is dominant over the tan coat color allele. In a population of mice, the frequency of the allele for mahogany coat color is 0.19 and the frequency of the allele for tan coat color is 0.81. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 100 mice?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

Part E

In humans, the free earlobe allele is dominant over the attached ear lobe allele. In a population of humans, the frequency of the allele for free earlobes is 0.42 and the frequency of the allele for attached earlobes is 0.58. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 25 humans?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

rubyleopard160

The genes for sepia eye color, short bristles, and dark body coloration are on the same chromosome of Drosophila melanogaster. Each gene has two alleles: wild type, which is dominant, or mutant, which is recessive.

se+ is dominant and causes red eyes; se is recessive and causes sepia eyes

sb+ is dominant and causes long bristles; sb is recessive and causes short bristles

b+ is dominant and causes gray body coloration; b is recessive and causes dark body coloration

The sepia gene and short bristle gene are separated by 32 map units; the short bristlegene and the dark body gene are separated by 13 map units. The sepia gene and dark bodygene are separated by 45 map units.

If you crossed a fly, which was homozygous for the wild type allele of each gene with a homozygous recessive fly for each gene, the F1 generation would entirely consist of flies that had the wild type traits, but were heterozygous for each gene.

If you were to cross these heterozygous F1flies to recessive homozygous flies, how many flies would you predict to have the double cross-over phenotype? (You will show all of your work and phenotypic classes in the next problem. Just show the NUMBER of double cross-over flies predicted by the map unit data here. Round to a whole number)

If you were to cross these heterozygous F1flies to recessive homozygous flies, how many flies would you predict to observe in each of the eight predicted phenotypic categories with respect to these three genes (given the map units above) if there were 1,000 total offspring? Please show work and show all phenotypic classes!