Class Notes (807,041)
Canada (492,563)
Anthropology (1,560)
ANTB15H3 (33)

ANTB15- Oct 7- lec 5.docx

5 Pages
Unlock Document

University of Toronto Scarborough
Larry Sawchuk

Lecture 5, Oct 7, 2013- Evolutionary Change Classical Genetic Markers 1. Simple inheritance (one gene) 2. No environmental modification 3. Easily scored and recognized 4. Vary from population to population (polymorphic – 2 or more alleles in the system) – example: ABO blood group system All classical genetic markers are Mendelian traits, but not all Mendelian traits make good genetic markers Little People Big World” (TLC) The Roloff Family  Matt Roloff diastrophic dysplasia (autosomal recessive)  Amy Roloff (achondroplasia), son Zach (achondroplasia) Achondroplasia • 1/26,000 to 1/40,000 births • Autosomal dominant – individual with achondroplasia has 50% chance (1 in 2) of producing offspring with achrondroplasia • NOTE: carriers not possible – the allele is either inherited or not – if allele is inherited, the trait will be expressed • Genetic counseling: scenario would shift if both parents have achondroplasia • 50% chance achondroplasia, 25% chance average stature, 25% homozygous achondroplasia (double dominant) • Est. 75% of cases born to average-size parents – in these cases, “de novo mutation” (spontaneous) has occurred • Achondroplasia – tied to gene located on Chromosome 4 (75% spontaneous mutation; 25% inherited) [reducing functioning of fibroblast growth factor receptor 3] 1. Genetic Markers: Blood types & Disease • Some Basics of blood types and ABO distribution • Molecular Genetic Markers 2. Blood type incompatibility: Hemolytic disease of the newborn Blood Types • Classic genetic markers • There are at least 60 Blood types that are polymorphic • ABO, Rh, MNSs, Kell, Duffy, Lewis • There are some blood types that are considered to be ‘private’ restricted to a family or small group of individuals, therefore useful for human genetics MN system and S= MNS system • Gene loci closely linked on 4 chromosome • Therefore genes transmitted as Ns • No antibodies for MN system The Duffy Blood Group • Two co-dominant genes for presence of antigen • natural selection in malaria prevalent areas Fy4 antigen does not have attachment for vivax • Est. Degree of admixture of European and African descent ABO Blood system H- system: lays down a precursor substance. Allows you to make A, B, or AB If you are homozygous (h/h), you will not display any of your blood type -> you’ll simply be old This particular genotype is called Bombay blood type, discovered in Bombay Bombay blood Type • Can not create A.B or H antigens, therefore neither blood type A,B or O • Is a homozygote recessive condition= hh • Will have anti-H antibodies • Commonly found in Mohorati speakers in and around Bombay North and South America: no B blood type Most common is blood type O Global Distribution of ABO blood types • Typically O is most common: 62.5% • A: 21.5% • B: 16% However population specific, great diversity in range of frequencies. Why? Differential in fertility and disease susceptibly= an evolutionary force operating??? Differential Fertility Type B mothers have more offspring Incompatibility of parental blood types: Type O mothers x A or B fathers have fewer offspring Type O mothers produce more O children than expected (>50%) because: • vagina may have anti-bodies for type A • anti-a and anti-b anti-bodies cross placenta and kills fetus • Blood type A suffer from various gastro-intestinal conditions • Secretors’ antigens may react with food molecules • Gut flora stimulate anti-body reaction (i.e. anti-B antibodies) • Most disease are post-reproductive and have no impact on reproductive fitness • Disease greater susceptibility • Cholera O • Plague O • Scarlet fever O and B • Smallpox A Balances out selection of type O as observed in increase fertility Blood type O has no antigen Some of these diseases mimic blood type O ABO • In interpreting the global distribution of A, B, and O alleles: Smallpox virus carries an
More Less

Related notes for ANTB15H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.