Osud skrytý v DNA aneb proč jsme ještě nevymřeli



Y
human_body
Silene latifolia  (10-20 MYA)        Homo sapiens  (240-320 MYA)
vs.
silene_latifolia_501
A     A
sex determining mutation
proto
X
proto
Y
suppression of recombination
accumulation of repeats
X     Y
X   0
   Silene latifolia
mammals
insects
loss of the Y chromosome
Y chromosome degeneration
X       Y

1891 Hermann Henking – spermatogenesis
           in Pyrrhocoris apterus (firebug)
Henking saw that some sperm cells had
12 chromosomes, while others had only 11.
Henking noticed that the mysterious twelfth chromosome
looked different from all the others.
He thus named this chromosome the "X element," to represent
its unknown nature.
1902 Clarence Erwin  McClung -THE ACCESSORY CHROMOSOME
Sex chromosomes - history
http://upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Pyrrhocoris_apterus_(aka).jpg/200px-Pyrrho
coris_apterus_(aka).jpg

Tenebrio molitor, Coleoptera
 ( F = AAXX, M = AAXY )
   mealworm
wilson
Nettie Stevens
Edmund Wilson

Past, present and future
of sex chromosomes
at the current rate of degradation, human Y chromosome
will likely lose its last 45 genes in just 10 million years
  X           Y

The presence of genes on the X chromosome that get expressed in the brain may allow more rapid
selection for favorable genetic variations which enhance cognitive function
Accumulation of „brain specific“ genes on the X chromosome

Human X chromosome and cancer genes
•Human X chromosome is almost depleted of cancer genes due to selection


The day after Y chromosome disappears
SRY has been lost in some rare rodents
and replaced by a new sex determining gene
So as the human Y runs out of options, new sex determining genes may evolve, leading to evolution
of different hominid species.
Ellobius lutescens – mole vole

Sex chromosomes in S. latifolia
 Gregor Mendel


Brünn, 27 September, 1870
C:\Users\Roman Hobza\Dropbox\Screenshots\Screenshot 2015-09-01 15.21.59.png
Carl Wilhelm von Nägeli
Gregor Johann Mendel
GREGOR MENDEL’S LETTERS TO CARL NÄGELI

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C:\Users\Roman Hobza\Dropbox\Screenshots\Screenshot 2015-05-18 15.04.59.png


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C:\Users\Roman Hobza\Dropbox\Screenshots\Screenshot 2015-05-18 15.01.12.png


Centrum strukturní a funkční genomiky



PhD students
Oddělení vývojové genetiky rostlin