This presentation has been supported by the Erasmus
Plus K2 Cooperation Partnerships.
Innovation of the structure and content of study programs in the field of animal
genetic and food resources management innovation.
with the use
of digitalization.
The European Commission support
for the production of this presentation does not constitute
and endorsement of the contents, which reflects the views only of the authors.
And the Commission cannot be held responsible for any use which may be made
of the information contained therein.
Ewa Wojcik works
for the Institute of Animal Science and Fisheries Faculty of Agrobioengineering
and Animal Husbandry in Siedlce University of Natural Sciences and Humanities.
She would like to present a lecture on chromosome basic of heredity.
The basic unit of heredity is a gene,
a unit that occupies a precise location called locus in the chromosome.
It has a linear series of nucleotides.
A gene acts as a storage unit of genetic information
responsible for replication, mutation and expression
It is found in the chromosome or outside the cell nucleus,
for example, inside the mitochondria and chloroplasts in plants.
A gene consists of a regulatory and structural part.
A chromosome is the structure of the cell nucleus that consists of DNA
RNA, histone and non histone proteins.
The specific packing of the chromatin in the chromosome allows in the metaphase
stage to perform various staining techniques that will show us
the anatomical features of these chromosomes.
For example:
Euchromatin, Heterochromatin, location of adenine-thymine,
pairs and location of guanine-cytosine pairs
In 1902
Sutton and Bovary correlated Mendel's theory of heredity
with the behavior of chromosomes during mitosis and meiosis.
This is the main conclusions as follows.
Genes are located on the chromosomes.
Chromosomes come in pairs.
One comes from the mother and the other from the father.
Homologous chromosomes are separated during meiosis.
After meiosis, the germ cells contain
one of the homologous chromosomes
genes are inherited according to the laws of Mendel.
In the fertilization process, the number of diploid chromosomes and alleles
is restored.
In the year 1919
chromosome theory of heredity was invented by Morgan
Morgan through his findings, he came to the following conclusions.
Genes are located in the chromosomes.
A gene occupies a specific place on a chromosome locus.
Genes in chromosomes are arranged linearly, genes are duplicated.
They go through a replication process.
Alleles of the same gene on homologous
chromosomes at exactly
the same locus.
Alleles of different genes occupy different positions
Genes
on the same chromosome form a group of linked genes.
There are as many linkage groups as there are pairs of chromosomes
in an organism.
For example, a piece with 80 chromosomes has 40 pairs
chromosome, so it has 40 linkage groups.
Only those genes
that lie on different chromosomes
and are unlinked are independently inherited
between homologous chromosomes.
Their fragments may be exchanged,
which results in the exchange of genetic information
genes called crossing over.
You sometimes find that process crossing the crossing over frequency
between genes is directly proportional to the distance between them.
The other question means the new the bigger the distance
between the genes, the higher the probability of this process occurring.
The map distance is expressed
as the ratio of the number of recombinants to the total number of offspring.
And this function is multiplied by 100%.
So the mapping unit is the centimorgan.
If the traits are linked with each other, that means the genes
have a common location on the same chromosome.
Then by crossing two DNA types,
one individual with a homozygous system
and an individual with a homozygous recessive system,
the gametes that will be formed will be AB dominant
and AB recessive gametes.
After the fusion of these two gametes, we have a heterozygous individual,
but the dominant genes are on one chromosome and the recessive genes are on the other chromosome.
in this individual.
The resulting heterozygous individual creates only two types of gametes
gamete consisting of dominant genes and gametes consisting of recessive genes.
After the merging of such
gametes, we form homozygous and heterozygous systems
where the heterozygous two dominant genes are on the same chromosome
and the recessive genes .
are on the other chromosome
Thank you
for your attention.
..