BIOL239 Lecture Notes - Lecture 1: Consanguinity, Quantitative Genetics

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pinkgiraffe357

4 Nov 2017

School

University of Waterloo

Department

Biology

Course

BIOL239

Professor

Christine Dupont

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Document Summary

Learning activity #1 notes: when looking at pedigree, we look at how a trait is inherited through several generations of a family group, the trait can be a disease or a morphological (structural) trait. Four possible modes of inheritance of a trait that are controlled by a single gene: autosomal dominant, autosomal recessive, sex-linked dominant, sex-linked recessive. Not looking at polygenic trait (those controlled by several genes). Generally, the more generations and individuals represented in a pedigree, the more conclusive our analysis can be. In some cases, the information that is presented in a pedigree points definitively to only one of the four possible inheritance patterns so that the analysis is conclusive. However, in some cases the information may fit more than one, or even all possible inheritance patterns. If a trait was rare in the population then most likely the inheritance pattern would be sex-linked dominant.

Related Questions

Imagine that you have a particular genetic trait and that you have four children. Two of the four children also possess this trait. Meanwhile, the other biological parent of your children does not possess the trait.

Explain why you think the trait in the scenario is dominant or recessive.

Based upon your response, describe why it would or would not be possible for the trait in the scenario to âskipâ a generation.

Patterns of inheritance within organisms like pea plants, fruit flies, mice, and others are somewhat easy to determine since their mating practices can easily be controlled. Apart from controlling who mates with whom, what other characteristics make species like these ideal for studying genetics?

Select and describe a health problem that you believe has a genetic component at least partially inherited. If you do not identify an inherited health condition within your family, choose a disease that interests you or impacts a friend or other family member. Would you be interested in having genetic testing to determine whether you carry a genetic mutation for a particular disorder or a genetic predisposition for a disease? Why/why not? What are the advantages and disadvantages of determining your predisposition?

Explore the current state of research for the health problem you selected. Focus on one of the following to discuss as they relate to the genetics of the disease:

Cause

Testing/Screening/Prevention

Treatments/Therapies/Cures

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

Leigh syndrome has several modes of inheritance and is incompletely penetrant and has variable expressivity, so it is possible for an individual to be affected with mild signs and symptoms, yet have children with a more severe form of the disease. Which of the following individuals would be at risk of having a child affected by Leigh syndrome? Leigh disease is rare, so assume in all cases that the individualâs partner carries no pathogenic variants related to Leigh disease. (select all that apply)

a mildly affected female homozygous for a pathogenic autosomal recessive variant

a mildly affected female homozygous for a pathogenic X-linked recessive variant

a mildly affected female with a pathogenic mitochondrial variant

a mildly affected male with a pathogenic mitochondrial variant

BIOL239 Lecture Notes - Lecture 1: Consanguinity, Quantitative Genetics

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