BIOL 1201 Lecture : 1201 Part 3 Notes

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azuremammoth471

15 Mar 2019

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The man may be heterozygous (iai) or homozygous. Sex-linked genes are carried on the sex chromosomes. Allele occurs on one of the sex chromosomes. In humans for the most part we are concerned with x-linked traits. Determines whether a son displays an x-linked trait. N= dominant allele for normal vision n= recessive allele. 99 encode proteins expressed in testis and in various tumor types. 168 mendelian diseases have been explained by mutation in 113 x-linked genes. Results in barr body: heterochromatin- tightly coiled inactive dna. Cells of woman are a mosaic for genes on the x chromosome. An individual with 2 barr bodies has how many x chromosomes. X chromosome inactivation at random, and all but one. Karl landsteiner discovered the abo blood groups in 1900. 1940 karl landsteiner and p. levine discovered the rh factor. Red blood cells from rhesus monkeys were used to produce antibodies in rabbits. Human red blood cells were tested with rabbit antibodies raised against.

Related Questions

1. A dramatic departure from expected phenotypic ratios may be theresult of
A. environmental influences.
B. linkage.
C. epistasis.
D. gene interactions.
E. All of the above

2. A woman of blood group A has a child with a man of blood groupB. The child's blood is type O. What are the genotypes of theparents?
A. Mother: IAIA; father: IBIa
B. Mother: IAiO; father: IBIb
C. Mother: IAiO; father: IBiO
D. Mother: IAiB; father: IBIO
E. It is impossible for these individuals to have a child with typeO blood.

3. In sex-linked inheritance of a recessive gene, all
A. male offspring of a normal male and a heterozygous femalecarrier would show the trait.
B. female offspring would be carriers.
C. male offspring who receive the mutant X chromosome would showthe trait.
D. female offspring who receive the mutant X would show thetrait.
E. Both b and c

A metallic blue-colored Indian blue peahen with long pinion feathers is crossed with a dull brown-colored Indian blue peacock with short pinion feathers. Half of the resulting peacocks are metallic blue with short pinions and half the resulting peacocks are metallic blue with long pinions. Half of the resulting peahens are dull brown with short pinions and half the peahens are dull brown with long pinions. Long pinions are the result of a functional protein. A) Which gene is sex-linked? B) What are the genotypes of each parent and each type of offspring?

Step 1: Determine whether either of the genes are sex-linked. For this type of a question, if you arenât told, then the thing for which to look is whether when looking only at the offspring one of the phenotypes sorts out by sex.

In this example, Half of the resulting peacocks are metallic blue with short pinions and half the resulting peacocks are metallic blue with long pinions. Half of the resulting peahens are dull brown with short pinions and half the peahens are dull brown with long pinions.

This suggests what is sex-linked, why?

Step 2: Determine the correct sex chromosomes (if needed) for the species. Step 3: put down allelic place holders for each individual

Peacock Father: _/_ _/_ Peahens Mother: _/_ _/_

Peacock Boys: _/_ _/_ Peahens Girls: _/_ _/_

Step 4 Figure out which allele is functional for each gene. To do this, look at individuals that will be heterozygous for alleles from mom and dad. For sex-linked traits, that would be the homogametic sex (ZZ or XX). For autosomal traits, all offspring will be informative

Step 5: Fill in what you know for sure based on phenotype:

Peacock Father: _/_ _/_ Peahens Mother: _/_ _/_

Peacock Boys: _/_ _/_ Peahens Girls: _/_ _/_

Step 6: Apply Rules 1 & 2 to deduce the unknown alleles:

Peacock Father: _/_ _/_

Peahens Mother: _/_ _/_

Peacock Boys: _/_ _/_

Peahens Girls: _/_ _/_

What are the genotypes of each parent and each type of offspring? Parents genotypes :

Offspring genotypes:

1. If you had a fruitfly with phenotype A, what test would you make to determine if it was Aa or AA? Explain the different outcomes expected if the fly in question is AA or Aa.

2.The sex of birds, some insects, and other organisms is determined by a ZW chromosomal arrangement in which the males have like sex chromosomes (ZZ) and females are ZW (similar to XY in humans). Assume that a recessive lethal allele on the Z chromosome causes death of an embryo in birds. What sex ratio would result in the offspring if a cross were made between a male heterozygous for the lethal allele and a normal female?

3.A recessive gene for red-green color blindness is located on the X chromosome in humans. Assume that a woman with normal vision (her father is color-blind) marries a color-blind male. What is the likelihood that this couple's first son will be color-blind?

4. One form of hemophilia is caused by a sex-linked recessive gene. Assume that a man with hemophilia marries a phenotypically normal woman whose father had hemophilia. What is the probability that they will have a daughter with hemophilia? (Note: In this problem, you must include the probability of having a daughter in your computation of the final probability.)

5. One form of hemophilia is caused by a sex-linked recessive gene. Assume that a man with hemophilia marries a phenotypically normal woman whose father had hemophilia. What is the probability that their first son will have hemophilia?

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BIOL 1201 Lecture : 1201 Part 3 Notes

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