New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Mendelian Genetics III

by: MaKena Betler

Mendelian Genetics III BIO 105 Cr.4

MaKena Betler
UW - L
General Biology
No professor available

Almost Ready


These notes were just uploaded, and will be ready to view shortly.

Purchase these notes here, or revisit this page.

Either way, we'll remind you when they're ready :)

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Lecture 29: Mendelian Genetics III
General Biology
No professor available
Class Notes
25 ?




Popular in General Biology

Popular in Biology

This 0 page Class Notes was uploaded by MaKena Betler on Tuesday November 17, 2015. The Class Notes belongs to BIO 105 Cr.4 at University of Wisconsin - La Crosse taught by a professor in Fall 2015. Since its upload, it has received 24 views. For similar materials see General Biology in Biology at University of Wisconsin - La Crosse.


Reviews for Mendelian Genetics III


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 11/17/15
Lecture 29 Mendelian Genetics Ill 0 Many species have distinct sexes which requires the action of distinct genes that control the developmental program for each sex 0 In humans there are two sex chromosomes X and Y that behave somewhat differently from the other 22 autosomes o X chromosome similar to the autosomes encoding 2000 genes little role in female development 0 Y chromosome severe reduction over the recent millennia and now encodes for less that 100 genes almost all of which are expressed only in the testes male gonads 0 Although the X and Y are very different in size and genecontent they have small regions near the ends that are homologous allowing them to pair during meiosis Human males 0 Human males contain an X chromosome from their mothers and a Y chromosome from their fathers Because males have only one copy of the X chromosomes they are hemizygous for the X encoded genes they only have one copy Human females 0 Females contain an X chromosome from each parent and without the Yencoded genes stick to the default 39female developmental pattern 0 Note that like the other 22 autosomes females can be heterozygous for the Xencoded genes whereas males have only one copy of all the Xencoded genes Sexlinked or Xlinked traits involve the genes encoded on the X chromosome the expressed phenotype can vary between males and females 0 Because all females have 2 Xchromosomes Recessive alleles for Xencoded genes will have no effect on the heterozygotes XNX Recessive alleles must be present as homozygotes X X to have any phenotype 0 However since males only ever have one Xchromosome Recessive Xencoded gene X will automatically have an effect in the hemizygous males 0 Females silence one copy of their X chromosome so that its gene are NOT expresses this happens in embryonic cells 0 Such silencing is visible since the inactive X chromosome is supercondensed down to an object called the Barr body o The choice of which X chromosome is inactivated in females is completely random and each cell in the early embryo chooses differently 0 So in the case of Xlinked genes that are heterozygous each woman is a mosaic of cells that express either the dominant or recessive trait Tortoiseshell cats are an example of the random nature of Xinactivation where different alleles of a coat pigment gene are expressed in different patches of the skin 0 One of the tools used by geneticists to study inheritance in humans because of the small number of progeny is pedigree analysis 0 When using pedigree analysis different patterns are found that can indicate whether traits are dominant recessive sexlinked or complex lf affected individuals showing a particular trait appear in every generation that trait is most likely dominant lf affected individuals showing a particular trait appear to skip a generation then this is a sign that a trait is likely recessive lf affected individuals are only or predominantly or one sex then it is very likely that the trait is sexlinked recessive Chromosomes have many genes and sometimes two trait loci are on the same chromosome they are linked o Unlinked genes like the owercolor and seed shape loci lie on different chromosomes you can assort individually during meiosis resulting in the 9331 segregation pattern 0 Linked genes like the ower color and pollen shape loci lie on the same chromosome and they cannot assort individually resulting in something that does not resemble a 9331 pattern instead it s almost closer to a 31 pattern o If the genes were on the same chromosome how d we get any purple round or whitelong plants These are called recombinant plants 0 Something has to happen to the chromosomes during meiosis to make recombinant gametes that can fuse to create the purple round or whitelongs o Recombinant chromosomes occur due to how the homologous chromosomes recombine form chiasmata during synapsis in meiosis metaphase l Recombination between the homologous chromosomes always occur during meiosis but the place recombination occurs is essentially random Recombination occurs at the same place where chiasmata form and is more simple called crossingover 0 Not all crossing over events on a chromosome will necessarily lead to recombination between two particular linked loci 0 Only those crossing over events that occur between the two loci will result in recombination Two loci very far apart will experience a crossing over event between them MORE OFTEN recombination is MORE frequent and the F2 will segregate very differently than 9331 Calculating distance on chromosome based on recombination frequency 0 Counting the phenotypic classes in the testcross progeny gives Parentals 2534 Recombinants 305 Total progeny 2839 o The percent age of the progeny that are recombinants the 305 recombinants recombination frequency 2 839t0mlpmgeny x100 107 o A map unit is equivalent to a recombination frequency of 1 which is equal to a centimorgan CM 0 Widely separated linked genes assort independently Chromosomal mutations that affect inheritance o Deletion ABC DEFGH AVD DEGH Duplication ABC DEFGH ABC DEDEFGH o Reciprocal translocation ABC DEFGH O I K LMN I ABC DEFGN I K LMFGH o lnversion ABC DEFGH ABC DGFEH 0 Some translocations can lead to cancer 0 The new translocation fuses the gene ABL to the gene BCR o The new gene BCR ABL is an oncogene The ABL gene is now MUCH more active Nondisjunction can cause whole chromosome abnormalities 0 Trisomy having three copies of chromosome 21 leads to down syndrome 0 Having the diploid amount of chromosomes is crucial for proper development


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Kyle Maynard Purdue

"When you're taking detailed notes and trying to help everyone else out in the class, it really helps you learn and understand the I made $280 on my first study guide!"

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.