1. Heredity
Chapter 14

2. Linked Genes
Genes may occur in patterns if two loci are on the same chromosome
During crossing over, these loci are so close they typically will remain together
Ex: blonde hair, blue eyes

3. Chromosome Mapping
The farther apart a gene is on a chromosome, the more likely they will cross over
Mapping a chromosome is a diagram of the loci the chromosome codes for

4. Karyotype A picture of chromosomes arranged in size order
Used to determine the sex of an individual and to see if there are any chromosomal disorders

5. Karyotype
Trisomy karyotype

6. Karyotype Monosomy karyotype
Only 1 14 – cru di chat
XO = turners syndromw

7. Sex Chromosomes/Autosomes
Contain genes that determine the sex of an individual (X & Y chromosomes)
Autosomes
Remaining chromosomes that do not determine sex of an individual (chromosomes 1-22)

8. Sex Determination
In mammals, egg cells only contain an X chromosome and sperm can either have an X or Y chromosome
If the new baby cell has XX  girl
If the new baby cell has XY  boy

9. Gene Location Sex-Linked genes
Characteristics that typically only show up in a certain sex of the organism
Ex: color blindness in males
Traits that are on one sex chromosome and not the other
CB Glasses:

10. Sex Linked Genes Colorblindness X = color vision, XC = colorblindness
Full color vision is dominant over colorblindness
X = color vision, XC = colorblindness
Colorblind male, color vision female
(homozygous)
Color vision male, color vision female (heterozygous)

11. Sex Linked Genes Eye Color in Drosophila
Red eyes are dominant over white
XR = red eyes , Xr = white eyes
Red eyed male, white eyed female
White eyed male, red eyed female (heterozygous)

12. X-linked Traits X-Linked traits are usually recessive
Males inherit X from mom which holds a huge amount of base pairs
If there is no other X to mask the trait, then the individual shows the X-linked trait
Individuals that have one copy of a recessive trait are known as carriers
Carriers do not express trait, but can pass to offspring

13. Sex-Influenced Traits
Males and females can show different phenotypes even if genotype is the same
Ex: pattern baldness
% higher in men due to higher levels of testosterone

14. Pedigrees Diagram that shows how a trait is inherited over generations
Male = 
Female = 

15. Pedigrees
Horizontal line between a male and female means they are married or have offspring
Vertical line between a male and female indicates offspring

16. Pedigree

17. Single-Allele Traits
Some traits are controlled by just one single dominant allele
Ex: Huntington's disease
If individual has one allele for this disease, they have it
There are no carriers

18. Mutations Change in a sequence of a gene
Germ-cell mutation (gamete/sex cell)
Change in the individual’s gametes
May be passed onto offspring
Somatic-cell mutation
Change in the individual’s body cells and can affect the person
Ex: skin cancer

19. Chromosomal Mutation Nondisjunction
When a chromosome fails to split during meiosis (anaphase) and sex cell chromosomes are uneven in number

20. Karyotype
Nondisjunction mutations in autosomes

21. Karyotype Nondisjunction mutations in sex chromosomes
Kleinfelter’s syndrome