J. G. Mendel
Augustinian friar and abbot
of St. Thomas' Abbey in Brno
Historical photo
of original green house of
Mendel Abbey in Brno
• Mendel was the first scienceman creating
inheritance theory? No. Since ages of faraons
and antical states, there were some archaic (less or
more mistake) theory:
• Aristotel (384 B.C.) Leevuenhoek (1632)
Opinion without any microscope Idea after see „ miniatur person in sperm!“
He did know anything bout X adn Y chromosome
• Why Mendel and other scienceman and doctors see the
basic law of heredity in last centuries and not erly?
Human life was very short to see the phenotype of parents and first generation
and second generation. However if scienceman use to good model organism, it si
possible to see to many generation in one year and make a idea about heredity.
DEFINITION: Heredity, also called
inheritance or biological inheritance,
is the passing on of traits from parents to their offspring;
either through asexual reproduction or sexual
reproduction,
• Skip …
• Skip back to 2nd law
This law is the most complicated.
Sometimes is ilustradet only by this P-F1 square, but
this is not exact definition of basic message for
clincal and biological application!! (it is only the
islutration of mendel science experiment which start
this hypothesis)
The law of independent assortment means that
separate traits of different alleles are inherited
by the zygote independently from each other.
Where the random selection of one allele for a
certain trait is not connected by any means to
the selection of another allele for a different
trait.
Independent assortment states that the
inheritance of various genes occurs
independently of each other. In the law of
independent assortment, the combination of
genes and their probability is calculated and
assumed by multiplying the probabilities of
each gene. Probability of having one gene does
not influence the probability of having the other.
• Note important aspect of mendelian genetic:
Phenotype profile vs. Genotype profile
Homozygote
Heterozygote
Dihybrid vs. Monohybrid
MENDEL SQUARES = sometimes are celled as PUNNET SQUARES
Some another typical ilustraion of MENDEL SQUARE for 1 gene
(2 variant of gene: G or g)
MENDEL SQUARES = sometimes are celled as PUNNET SQUARES
Some another typical ilustraion of MENDEL SQUARE for 3 genes (3 phenotypic marker)
(2 variant of all genes)
AUTOSOMAL RECESIVE GENES (ILLNESS)
vs.
AUTOSOMAL DOMINANT GENES
RECES. DOMINAN.
Reces. Domin.
Learn example
Summary of basic mendelian genetic
• Mendel was the first, who derived from mathematical result of experiment with P
(parent), F1 (firt generation) and F2 (second generation) the opinion, that 2 variant of
genetic informatin must be in all parental cell, and only one of this variant is shifted to
egg or sperm.
• Mendel never see something like chromosome or DNA. DNA was recognised and
structuraly investigatedy more than 100 year later. However these modern microcopic
techniq and biochmeistry investigation.
• Mendel law about SEGREGATION and DOMINANCE can be aplied in all modern
descripton of inheritance of important marker of all human and most of the animal
(pigment, enzyme aktivity, muscle components of patients) and alos in desription of
inheritance of many pathology (anemia, schizophremia, some type of cancer, …)
• NOT ALL INHERITANCE PHENOMENON visible in modern medicine in specific
pathology, can be described only by 3 MENDEL LAW. There must be add also
some antoher modern laws o genetic: MORGAN LAW, Law of incomplete
dominance, Law of codominace and Rules of non-independent genes. (In next lecture
material)
Additive non-mendelian rules
Some GENETIC mistakes
from
high school and internet pages
(1) EYE
Blue and green eye phenotype is somewhere in textbook
described as simple Mendel dominant/recesive gen
cooperation (on left picture). The reality is little bit different (on right)
.
Reality:
Hans Eiberg --- Human Genetics volume 123, pages177–187 (2008)
The human eye color is a quantitative trait displaying multifactorial
inheritance. Several studies have shown that the OCA2 locus is the
major contributor to the human eye color variation
Not exact theory
(only for several family):
Some high school textbook
See the article
https://link.springer.com/article/10.1007/s00439-
007-0460-x
GENETICmistakes
(2) Cancer screening
Women with mutations in either BRCA1 and BRCA2 do have a five-fold
increased risk of breast cancer compared with other women. But many did
not know that these mutations are rare: far less than one percent of women
have them.
Most people also still don’t know that the BRCA mutations are only linked
to five to 10 percent of all breast cancer cases. And that in terms of
absolute numbers, many more women with no family history of the disease
get diagnosed with breast cancer than do those with a history of breast
cancer in the family.
GENETICmistakes
(3) Diabetes type II – has one typical gene?
No, there is the set of gene. And also some
genetic change in INTRON of genome!!
ARTICLE
https://www.researchgate.net/figure/Maj
or-susceptibility-genes-and-pathogenic-
mechanisms-for-type-2-diabetes-
identified-so_fig9_41510100
Major susceptibility genes and
pathogenic mechanisms for type 2
diabetes identified so far (2008).
SNP = Single-nucleotide
polymorphism;
CGA = candidate gene approach;
GWA = genome-wide association;
LSA = large-scale association.
GENETICmistakes