1. GENES AND CHROMOSOMES

2. The Chromosome Theory of Heredity
Traits are determined by pairs of genes (alleles)
A pair of genes are located on a pair of chromosomes, one gene for each trait on each chromosome of a pair.
In meiosis, the chromosomes and therefore the genes, segregate independently – one of each pair to a gamete
In fertilization, gametes unite resulting in a fertilized egg that has two genes for each trait carried on pairs of chromosomes.

3. SEX DETERMINATION AND CHROMOSOMES

4. Homogametes Heterogametes
A. XX-XY CONDITIONS
IN DROSOPHILA: 2n= 8
P: (6 + XX) ♀ (6+ XY) ♂
G: ( 3+ X); (3+X) (3+X) (3+Y)
Homogametes Heterogametes
Autosomes
(somatic chr)
meiosis
Gonosomes
(sex chr)
6 + XO ♂
6 + XXY ♀
6 + YO zygote dies

5. IN HUMANS: 2n= 46 P: (44 + XX) ♀ (44+ XY) ♂
G: ( 22+ X); (22+X) (22+X) (22+Y)
Homogametes Heterogametes

6. 44 + XO ♀ (TURNER SYNDROME)
44 + XXY ♂ (KLINEFELTER SYNDROME)
44 + YO ZYGOTE DIES
44 + XXX SUPER FEMALE
44 + XYY POSIBLE SERIAL KILLER*

7. (TURNER SYNDROME)

10. (KLINEFELTER SYNDROME)

12. SUPER FEMALE

14. Heterogametes Homogametes
B. ZZ-ZW CONDITION
IN CHICKENS: 2n= 18
P: (16 + ZW) ♀ (16 + ZZ) ♂
G: ( 8+Z); (8+W) (8+Z) (8+Z)
Heterogametes Homogametes

15. Homogametes Heterogametes
C. XX-X0 CONDITION
IN GRASSHOPPER: 2n= 24
P: (22 + XX) ♀ (22 + X0) ♂
G: (11+X); (11+X) (11+X); (11+0)
Homogametes Heterogametes

16. G: D. HAPLOID –DIPLOID CONDITION IN HONEYBEES:
P: (QUEEN) ♀ 2n= (DRONE) ♂ n= 12 G:
meiosis
mitosis
eggs n n n n
sperm n n
fertilization
parthenogenesis
Female larvae (2n)
Differentiaton due to difference in diet
Male larvae (n)
QUEEN
WORKERS
DRONES

17. In some species of animals, sex is determined by environmental conditions or by the presence or absence of the opposite sex
Bonellia, If there is more of female individuals in the population, the larva develops into male, which is very small and lives as a parasites in the reproductive system of the female.
In amphibians sex determination is affected by temperature of the environment, and also by hormones.

18. In certain annelids, when the number of segments of the organism is small, it is a male. When the number of segments increase, the organism becomes female.

22. COLOR BLIND PEDIGREE MAP

24. dominant inheritance

25. recessive inheritance

26. 1. Determine if the trait recorded in the pedigree below is dominant or recessive and sex-linked or not. Which of the lettered individuals carry an allele for the trait. a b c d e f

27. 2. Determine if the trait recorded in the pedigree below is dominant or recessive. Is it sex-linked or not? b d e a c

28. 3. Below is a pedigree for four generations of a family, some of whose members exhibit a particular trait. From the information in the pedigree, determine if the trait is dominant or recessive, and sex –linked or not sex-linked. Which of the lettered individuals is a carrier- that is, heterozygous-for the trait? a c b d

29. 4. Determine if the trait recorded in the pedigree below is dominant or recessive and sex-linked or not. Which of the lettered individuals are heterozygous for the trait? b a c f e d

30. 5. The pedigree below shows the blood types of some individuals
5. The pedigree below shows the blood types of some individuals. List all the possible genotypes of each lettered individuals. O A B e d AB a b c f