HMB265H1 Lecture Notes - Lecture 7: Allosome, Y Chromosome, Meiosis

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rosebadger889

3 Oct 2017

School

UTSG

Department

Human Biology

Course

HMB265H1

Professor

Maria Papaconstantinou

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HMB265H1 Full Course Notes

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Hmb265: lecture 7 - meiosis and the chromosomal theory of inheritance (sept. 29) Complementation: mutations have to be recessive (phenotype must be recessive) Chromosome theory of inheritance theory that genes are located on chromosomes. Male gametes contained 11 chromosomes and x or y in equal numbers. Propose that x and y chromosomes were responsible for determining animal sex. If took y-bearing sperm fertilized to x-bearing egg, got xy male individual. If took x-bearing sperm fertilized to x-bearing egg, got xx female individual. Say dark green from mother, light green from father. Dark red from mother, light red from father. Same size, shape, contain same set of genes. But for some genes have different alleles. These chromosomes have undergone chromosomal replication just before cell division. Green and red are not homologous pairs. Metaphase chromosomes classified by position of centromere. Gametes created via meiosis, somatic cells created via mitosis. Dna replication occurs during s phase of interphase.

Related Questions

Biology lab homework

Dragon Genes

http://www.concord.org/stem-resources/modern-genetics

BLY 121L - Take HomeAssignment

Due: Start of class time âAt thestart of class next week

Answers MUST beâ¦

â¢ typed (no smaller than 11-pointfont)

â¢ complete sentences (i.e., grammaticallycorrect â AND spell check!)

â¢ THIS IS NOT AGROUP EFFORT â NO POINTS WILL BE AWARDED, IF YOUR PAPER ISSIMILAR IN CONTENT AND WORDING TO THAT OF YOURPEERâS.

Complete ALL4 modules:

1. Intro& Rules

2. Meiosis

3. Pedigree andGenes

4. The PlatesProblem

Complete and answer all of the questions fromeach module.

Introduction

Breed dragons to yield several offspring anddevelop a chart for all of the phenotypic characteristics youobserve.

â¢ Note the genotype and dominant/recessivecondition for each trait.

â¢ When you reach this section of theexercise, be sure to change the genotype for all traits to completethe chart.

Whatare the traits exhibited by yourdragons?

**YOUMUST TURN IN YOURCOMPLETED CHART AND IT MUST BE LEGIBLE!

Rules

Dominance and Recessive Traits

What isthe chromosome number(ânâ) for thedragons?

Which trait(s)exhibit incompletedominance?

What does it mean fora trait to be incompletely dominant?

Noallelic combination is described as being heterozygousrecessive. Why do you thinkthis is thecase?

Some Traits are Sex-linked

Which dragontrait(s)is/are sex-linked?

How dosex-linked traits differ from autosomal traits?

Color and Lethal Combinations

Describehow the inheritance ofcolor is different from that of horns and/orwings.

On whichchromosome is the lethal combination exhibited? What is the lethalcombination?

Meiosis

What is the phenotypeof your new dragon?

Whichtraits areinherited from the mother dragon? AND Which traits are inherited from the father dragon?

Wereany traits expressed by the offspring that differed from either or both of the parents? If so, whatwere they?

How does meiosisallow for variation inoffspring?

How doesfertilization allow for variation in offspring?

Pedigree and Genes

Now that you know how to breed dragons, let'stry some selective breeding in the pedigree view. Use the cross tool tobreed a new generation of dragons; breed two of thedragons from this new (F1) generation. Repeat thisat least8 times.

What do younotice about the dragons as you continue to breed more generations?

Use the chromosome tool to closelyexaminethe dragonsâ genes. If you had trouble answering the sex-linkedquestion above, now you can observe and compare the Xand Y chromosomesâ¦

Can you find any genesthat are different among the members of your F8generation?

How many generationsdo you have to breed until all the dragons are exactly thesame?

You arecreating an inbred strain of dragons in the final generation(s)of this process. Write a notedescribing your strain, and explain what is âspecialâ aboutall individuals in an inbred strain of organisms.

The Plates Problem

Try breedingsome offspring to see resultsof these crosses. Does thepattern of inheritance ofplates tell you anything useful?

Based on yourbreeding experiments, where might you expectto find the gene forplates (i.e., On whichchromosome might the gene be located?) Why do you think this iscorrect?

Dragons thatgrow plates usually do so quite late in their life, so dragons thathave a new baby don't know right away whether or not it will growplates. Which trait(s)exhibited by a baby might helpa mother dragon determine whether her baby will growup to have plates?

DragonGenes
Genotypes/Phenotypes

Trait	Phenotype	Genotype
Horns	Horns
	No Horns
Wings	Wings
	No Wings
Legs	4 Legs
	2 Legs
	No Legs
Tails	Fancy Tail
	Plain Tail
Fire-breathing	Fire-breathing Male
	Non-fire-breathing Male
	Fire-breathing Female
	Non-fire-breathingFemale
Color	Green Male
	Yellow Male
	Red Female
	Blue Female
	Brown Female
	Purple Female

olivedonkey40

1.A homozygous red-eyed female Drosophilamates with a red-eyed male Drosophila. What proportion of thefemale offspring will have white eyes?

75%

25%

100%

2.Red-green colorblindness is a recessive X-linked trait.If a female is red-green colorblind, which of the following isTRUE?

Her father mustbe colorblind.

Both herparents are carriers of the recessive allele.

Both herparents must be colorblind.

Her mother mustbe colorblind.

Women cannotexhibit red-green colorblindness because they have two Xchromosomes.

3.Allelesare

recessive traits.

dominant traits.

exact copies of the same trait.

alternate versions of the same trait

4.Using three bases torepresent each amino acid in a polypeptide

ensures that other organisms can read the codetoo.

prevents the wrong amino acid from being incorporated into aprotein.

ensures that DNA can replicate properly.

ensures that all amino acids are represented at least once bythe code.

5. If an organism's DNA contains 20%adenine nucleotides, what percentage of its DNA is composed ofguanine nucleotides?

6. Atrue-breeding tall pea plant is crossed with a tall pea plant ofunknown parentage. Which of the following iscorrect?

Some shortindividuals may appear in the F2 generation.

Some of the F1generation will be short.

All of theoffspring (F1) will be short.

Over severalgenerations, no short individuals will appear.

7.Morgan breeds and sells snakes. He knows that he can makethe most money by breeding and selling albino snakes. Albinism is arecessive trait. His female albino corn snake just produced 6offspring. Two displayed normal coloration and 4 were albino. Whatdo you know about the genotype of the father?

He could beeither heterozygous or homozygous dominant.

He must behomozygous recessive.

There is notenough information to determine the father's genotype.

He must beheterozygous.

8.During the elongation cycle of translation, the A site ona ribosome functions in

releasing thecompleted polypeptide.

holding apolypeptide as amino acids are added.

attaching thesmall subunits of rRNA to the large subunit.

receiving a newtRNA with the correct amino acid.

9.Whichof the following is an incorrect match?

translation -polypeptide formation

transcription -tRNA formation

translation -mRNA binding to rRNA

replication -copying of DNA

10. Thethree steps that are required for DNA replicationare

base doubling,unwinding, and joining.

unwinding, basedoubling, and base pairing.

unwinding,complementary base pairing, and joining.

unwinding,transcription, and translation.

11.Thex-ray diffraction pattern of DNA discovered by Rosalind Franklinshowed that DNA

contains alphahelices and beta sheets.

contains betasheets arranged in a repeated pattern.

has a repeatedpattern.

is both helicaland has a repeated pattern.

12.Which of the following is TRUE?

All traits onthe sex chromosomes are associated with sexual development.

Females can beheterozygous for sex-linked traits.

Males areheterozygous for the SRY gene.

Men pass theirX-linked traits to their sons.

13.Martha has a widow's peak and attached earlobes. Martha's dad had astraight hairline and unattached earlobes. What is Martha'sgenotype?

Answer withBRIEF EXPLANATIONS please

if more than 2answers you given are wrong, low star, pretty much no pts!

indigojackal331

1. A species of flowering plant includes plants with blooms that range from bright golden yellow to very pale yellow; no flowers carrying the yellow pigment allele appear white. The allele for yellow flower color:

a. must be a suppressor of another allele.
b. demonstrates incomplete penetrance.
c. demonstrates variable expressivity.
d. must be a modifier of another allele.
e. demonstrates variable penetrance.

2. Coat color in mice is determined by two alleles acting at a single locus: B is dominant and results in mice with black coats, and b is recessive and results in mice with white coats. In a litter of 12 mice, nine are black (B/â) and three are white (b/b). What is the penetrance of the B coat color allele?

a. zero
b. 25 percent
c. 50 percent
d. 75 percent
e. 100 percent

3. Semisterility in nearly 50 percent of the progeny they produce is often an indication that:

a. the parents are translocation heterozygotes.
b. both parents carry pericentric inversions.
c. both parents carry polytene chromosomes.
d. one of the parents carries a chromosomal deletion that removes a telomere.
e. one of the parents carries a chromosomal deletion that removes a chromosome's centromere.

4. A researcher is studying melanoma cells derived from a patient's skin tumor. He determines that all melanoma cells are 2n + 1, but the chromosome number in all normal skin cells is 2n. The 2n + 1 melanoma cells likely arose from:

a. mitotic nondisjunction.
b. meiotic nondisjunction.
c. mitotic recombination.
d. parthenogenesis.
e. colchicine treatment.

5. Why won't a balancer chromosome in Drosophila produce viable crossover products when paired with a wild-type chromosome?

a. Balancer chromosomes contain multiple inversions.
b. Balancer chromosomes contain multiple deletions.
c. Balancer chromosomes have no centromere.
d. Balancer chromosomes have no telomeres.
e. None of the answers is correct.

6. A doctor notes that a patient's genome contains 100 potentially harmful recessive mutations; however, the patient is heterozygous for all of the loci considered and thus does not demonstrate any abnormal phenotypes. The 100 recessive mutations the doctor discovered represent the patient's:

a. bivalents.
b. monosomy.
c.genetic load.
d. amphidiploidy.
e.nondisjunction.

7.The term describing the relationship between the number of copies of a gene and how much product is made from the gene is:

gene-dosage effect.
gene balance.
dosage compensation.
transcription.
aneuploidy.

8. The gene for upright ears in rabbits has two alleles. The E allele is dominant and results in upright ears, and the recessive e allele results in droopy ears. Of 100 rabbits surveyed, 87 had a genotype for upright ears (E/â). However, only 72 of these 87 rabbits had upright ears; the remaining 15 rabbits had completely droopy ears. This suggests that the allele for upright ears:

a. has incomplete penetrance.
b. has complete penetrance.
c. demonstrates variable expressivity.
d. is lethal.
e. is incompletely dominant.

9. A researcher has selfed an autotetraploid plant with the genotype D/D/d/d, and in the resulting progeny she observes a 35:1 phenotypic ratio. What can she conclude from this observation?

a. The progeny from this cross do not demonstrate a standard Mendelian phenotypic ratio.
b. In the 35:1 phenotypic ratio, the 1 represents the phenotype of the d/d/d/d progeny.
c. During meiosis in the D/D/d/d parent plant, it is likely that only bivalents, no quadrivalents or trivalents, formed.
d. It is likely that in this plant species, gametes associate with one another randomly.
e. All of the answers are correct.

10. A researcher is studying fur color in a new species of bats. He notices that fur color, which is due to the presence of a dominant allele (G), ranges from light gray to very dark gray. In addition, some bats that carry a G allele have no fur pigmentation whatsoever; their coats appear white. This is an example of:

a. only variable expressivity.
b. only incomplete penetrance.
c. both variable expressivity and incomplete penetrance.
d. recessive allele lethality.
e. pleiotropy.

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HMB265H1 Lecture Notes - Lecture 7: Allosome, Y Chromosome, Meiosis

HMB265H1 Full Course Notes

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