DOC PREVIEW
WSU BIOLOGY 107 - Chromosomal Basis of Ineritance

This preview shows page 1 out of 4 pages.

Save
View full document
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

BOLOGY 107 Lecture 23 Outline of Last Lecture I Genetics a Punnett square b Laws of independent assortment c Probability d Test cross Outline of Current Lecture II III IV V Test Cross Misconceptions Extensions of Mendelian Genetics Pedigree Analysis Chromosomal Basis of Inheritance Current Lecture Test Cross Misconceptions 1 Probability vs outcome a With a few number of progeny it is possible to have a heterozygous parent and only progeny showing the dominant phenotype i A greater number of progeny helps correct this ii Once there is one progeny with the recessive phenotype the parent is deemed heterozygous 2 Dominance vs predominance a Frequency of a genotype in a population does not mean the allele is dominant or recessive i Genetic dominance is determined by the biochemical process of the gene ii Predominance is decided by fitness selection and or genetic drif Extensions of Mendelian Genetics 3 Incomplete dominance a Neither allele is completely dominant i Heterozygote intermediate blending 4 Codominance a More than two alleles for a gene more than one is dominant i Example blood types 1 A and B are both dominant genotypes over O AB is a possible blood type These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 5 Epistasis a One gene affects the expression of another i Example Labrador retriever 1 One gene determines coat color brown or black while another determines if the color pigments are deposited in the hairs If the pigments are not deposited a white haired or yellow lab is observed 6 Polygenetic inheritance a Two or more genes affect the same phenotype i Only happens with quantitative traits such as skin color or height where a spectrum occurs rather than this or that basis 7 Environmental effects a Expression of a gene can be determined by environmental factors i Example flower color 1 Some flowers of the same plant with the same genotype show a different phenotype for petal color in different pH environments 8 Pleiotropy a One gene affecting multiple phenotypes i Example pea genetics 1 Petal color and color of seed casing are determined by the same gene b Different from polygenic i One gene for many phenotypes vs many genes for one phenotype 9 Mosaicism and related phenomena a Rise from cells with different dominant genotypes in the same individual i Causes 1 Mutation afer initial cell division 2 Zygotes or embryos fuse 3 Chromosomal inactivation a Inactivating one of the copies of a chromosome Pedigree Analysis 10 Analysis of inheritance patterns based on extended family information a Draw pedigree based on phenotypes and if any know genotypes b Deduce dominant vs recessive traits and genotypes of individuals i Used when test crosses cannot be preformed ii Dominant traits do not skip a generation 11 Inherited disorders a Recessive disorders i No functional copy of a gene for a parent to show the phenotype ii Heterozygotes show normal phenotype but carry the affected gene iii Example Albinism b Dominant disorders i Only one affected gene is required to show the phenotype 1 Protein is created that actively creates the problem ii Can be no carriers iii Rare in population 1 Affect reproductive fitness so not likely to be passed excludes Huntington s disease 2 Homozygotes are severely affected high fatality early c Partial dominance i Sickle cell anemia 1 Shown by globin misshape 2 Heterozygotes only show signs in a low O2 environment 3 Resistant to malaria explains retention Chromosomal Basis of Inheritance d Genes are DNA sequences at loci specific locations on chromosome e Explains violations to Mendel s laws 12 Fruit fly a Thomas Morgan discovered sex link traits and crossing over of chromosomes b Drosophilia model i Easy to breed many progeny sort generation ii Easy to induce and identify mutations iii Only 8 chromosomes 1 Three variant pairs and one sex determining pair iv Have polytene chromosomes 1 Salivary glands make 1000 copies of chromosomes 2 Self associate to form chain with visible banding 3 Easily view deletions and mutations v Wild type phenotype shown in the wild population denoted with a like W c Parent generation crossed Red eyed female with a white eyed male i F1 generation all had red eyes ii F2 generation 3 1 ratio with red eyes female had a 2 0 red eye ratio male had a 2 1 red eye ratio iii Morgan determined red eye gene was on female chromosome d Sex determination i XY human female is XX male is XY ii XO grasshoppers female is XX male is X iii ZW chicken female is ZW male is ZZ iv Diploid vs haploid bees female is diploid male is haploid 13 Human sex genes a Male determines sex of the child i Autosomal exist in homologous pairs no matter the sex ii X chromosome 800 genes unrelated to sex iii Y chromosome 40 80 individual genes 1 Pseudoautosomal regions pair wit X chromosome during meiosis 2 Two genes have homologous pairs on the X but do not pair or cross over 3 A dozen genes are unique to Y chromosome relate to male differentiation and development iv X inactivation 1 Only one X chromosome is active in mammals random inactivation 2 Possibly used as dosage compensation of genes


View Full Document

WSU BIOLOGY 107 - Chromosomal Basis of Ineritance

Documents in this Course
Exam 1

Exam 1

3 pages

Load more
Download Chromosomal Basis of Ineritance
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Chromosomal Basis of Ineritance and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Chromosomal Basis of Ineritance and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?