Podstawy genetyki
mendlowskiej
I Prawo Mendla
I Prawo Mendla 
reguły przekazywania cech dziedzicznych
" Pierwsze prawo Mendla (prawo czystości gamet)  każda gameta wytwarzana
przez organizm posiada tylko jeden allel z danej pary alleli genu.
" Wynika z tego, że każda komórka płciowa musi zawierać po jednym genie z każdej
pary alleli.
" Przy tworzeniu się gamet allele jednego geny wykluczają się = do jednej gamety
przechodzi zawsze tylko jeden allel danego rodzaju.
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
The smooth F2 plants segregate in F3 while the wrinkled ones breed true
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
A single-gene model explains Mendel s ratios
Figure 2-12 part 1
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 2
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 3
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 4
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 5
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 6
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 7
Szachownica Punnetta (Punnett square) - przedstawia wszystkie
możliwe kombinacje typów gamet w czasie zapłodnienia.
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 8
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 9
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 10
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 11
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 12
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 13
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 14
A single-gene model explains Mendel s ratios
A single-gene model explains Mendel s ratios
Figure 2-12 part 15
Podstawy genetyki
mendlowskiej
Krzyżówka testowa
Krzyżówka testowa
" Krzyżówkę testową wykonuję się zawsze gdy chcemy sprawdzić czy dany osobnik jest heterozygota.
" Jest to typ krzyżówki z dziedziczeniem fenotypowym 1:1.
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
Taki układ fenotypów (1:1) jest spotykany np. w rodzinach gdzie jeden z rodziców posiada
rzadki dominujący allel odpowiedzialny za występowanie pląsawicy Huntingtona.
http://upload.wikimedia.org/wikipedia/commons/1/13/Autodominant.svg
Podstawy genetyki
mendlowskiej
Human single gene disorders
- Mendelian inheritance patterns
What can Gregor Mendel s pea plants tell us about human disease?
" Single gene disorders, like Huntington s disease and cystic fibrosis, actually follow
Mendelian inheritance patterns.
Type of Inheritance Example Gene Responsible
Autosomal dominant Huntington's disease Huntingtin (HTT)
Autosomal recessive Phenylketonuria Phenylalanine hydroxylase (PAH)
Cystic fibrosis Cystic fibrosis conductance
Mukowiscydoza regulator (CFTR)
Sickle-cell anemia Beta hemoglobin (HBB)
Anemia sierpowata
Oculocutaneous albinism OCA2
Chial, H. (2008) Mendelian genetics: Patterns of inheritance and single-gene disorders. Nature Education 1(1)
Examples of Human Diseases, Modes of Inheritance, and Associated Genes
Disease Type of Inheritance Gene Responsible
Phenylketonuria (PKU) Autosomal recessive Phenylalanine hydroxylase (PAH)
Cystic fibrosis Autosomal recessive Cystic fibrosis conductance transmembrane regulator
(CFTR)
Sickle-cell anemia Autosomal recessive Beta hemoglobin (HBB)
Albinism, oculocutaneous, type II Autosomal recessive Oculocutaneous albinism II (OCA2)
Huntington's disease Autosomal dominant Huntingtin (HTT)
Myotonic dystrophy type 1 Autosomal dominant Dystrophia myotonica-protein kinase (DMPK)
Hypercholesterolemia, autosomal dominant, Autosomal dominant Low-density lipoprotein receptor (LDLR); apolipoprotein
type B B (APOB)
Neurofibromatosis, type 1 Autosomal dominant Neurofibromin 1 (NF1)
Polycystic kidney disease 1 and 2 Autosomal dominant Polycystic kidney disease 1 (PKD1) and polycystic kidney
disease 2 (PKD2), respectively
Hemophilia A X-linked recessive Coagulation factor VIII (F8)
Muscular dystrophy, Duchenne type X-linked recessive Dystrophin (DMD)
Hypophosphatemic rickets X-linked dominant Phosphate-regulating endopeptidase homologue, X-
linked (PHEX)
Rett's syndrome X-linked dominant Methyl-CpG-binding protein 2 (MECP2)
Spermatogenic failure, nonobstructive, Y- Y-linked Ubiquitin-specific peptidase 9Y, Y-linked (USP9Y)
linked
Chial, H. (2008) Rare genetic disorders: Learning about genetic disease through gene mapping, SNPs, and microarray data. Nature Education 1(1)
OMIM � - Online Mendelian Inheritance in Man �
Trends in Gene Discovery
" After the human genome was sequenced, researchers began to shift their focus from
monogenic diseases to polygenic diseases, which involve many genes. There are
several reasons for this movement toward polygenic diseases.
" For one, many of the 1,621 monogenic disorders without known genes are very rare.
" As a result, researchers face difficulties in identifying families with the disease and in
obtaining sufficient numbers of DNA samples for comparison to unaffected family
members.
" Also, funding agencies, biotechnology companies, and pharmaceutical companies are
often less likely to invest financial resources in research efforts focused on rare
diseases.
" However, studies of monogenic diseases contribute a great deal to knowledge of
polygenic forms of human disease (Antonarakis & Beckmann, 2006). To this end,
monogenic diseases are most worthy of our attention.
2008 Nature Education
Podstawy genetyki
mendlowskiej
Krzyżówka dwucechowa
Krzyżówka dwucechowa
" The coat color gene and seed
shape genes assort (segregate)
independently.
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
Mendel s breeding program that produced a 9 : 3 : 3 : 1 ratio
Figure 3-3 step 1
Mendel s breeding program that produced a 9 : 3 : 3 : 1 ratio
Figure 3-3 step 2
Mendel s breeding program that produced a 9 : 3 : 3 : 1 ratio
Figure 3-3 step 3
Mendel s breeding program that produced a 9 : 3 : 3 : 1 ratio
Figure 3-3 step4
Mendel s breeding program that produced a 9 : 3 : 3 : 1 ratio
Figure 3-3 step 5
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 1
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 2
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 3
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 4
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 5
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 6
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 7
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 8
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 9
Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1 ratio
Figure 3-4 step 10
Genotype and phenotype ratios in the F2 of a dihybrid cross
" Frekwencja 9:3:3:1 jest prostą kombinacją stosunku 3:1 dla alleli dwóch
genów dziedziczących się (segregujących) niezależnie.
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
Podstawy genetyki
mendlowskiej
II Prawo Mendla
A testcross can be used to show two genes are unlinked
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
A trihybrid cross produces a 9:3:3:1 ratio of phenotypes
Figure 3.12: With independent assortment, the expected ratio of phenotypes in a trihybrid cross is obtained by multiplying
the three independent 3:1 ratios of the dominant and recessive phenotypes.
Hartl i Jones (2009) Genetics: Analysis of Genes and Genomes
Pytania ?