The document discusses the human Y chromosome. It notes that the Y chromosome contains 58 million base pairs, comprises 1% of the DNA in a male cell, and contains 86 genes that code for 23 proteins. It is smaller than the X chromosome and does not recombine with it except in small pseudoautosomal regions. The bulk of the Y chromosome that does not recombine is called the non-recombining region.

1. Fatemeh Shahab & Alireza Zenhari

2.  58 million base pairs (the building blocks
of DNA)
 1% of the total DNA in a male cell
 contains 86 genes, which code for only 23
distinct proteins
 Acrocentric
 Smaller than X

3. ‫کروموزوم‬ ‫های‬ ‫وژن‬ ‫ها‬ ‫ویژگی‬Y
‫های‬ ‫وژن‬ ‫ها‬ ‫ویژگی‬‫کروموزوم‬X
‫کروموزوم‬ ‫تشابه‬ ‫وجه‬X‫و‬Y
‫کروموزوم‬ ‫تکاملی‬ ‫سیر‬Y
‫کروموزوم‬ ‫تحول‬ ‫گر‬ ‫بیان‬ ‫تکاملی‬ ‫های‬ ‫نظریه‬Y

4.  The human Y chromosome is unable to
recombine with the X chromosome, except
for small pieces of pseudoautosomal
regions at the telomeres (which comprise
about 5% of the chromosome's length).
 The bulk of the Y chromosome which does
not recombine is called the "NRY" or non-
recombining region of the Y chromosome.

5. 47,XXY Klinefelter syndrome 45,X Turner Syndrome (XO)
male female
tall stature short stature
testes do not mature rudimentary ovaries
sterile sterile
lowered IQ is common IQ typically normal
1/700 male births 1/3000 female births
47,XYY Double-Y syndrome 47,XXX Trisomy-X syndrome
male
above average height, otherwise phenotypically
normal.
At one time, it was claimed that XYY males are prone
to violent or antisocial behavior, based on elevated
incidence of 47,XYY among incarcerated men. Now
thought to be due to higher incidence of moderate
mental retardation than for XY males.
many phenotypically normal
the frequency of lowered IQ is higher than among
XX females.
Sex chromosome aberrations

6. ◦ These regions are called the pseudoautosomal regions., PAR1 and PAR2.
◦ a crossover in PAR1 is necessary in male meiosis to get proper segregation
of the chromosomes.

8. ◦ AZF1 (azoospermia factor 1)
◦ BPY2 (basic protein on the Y chromosome)
◦ DAZ1 (deleted in azoospermia)
◦ DAZ2
◦ PRKY (protein kinase, Y-linked)
◦ RBMY1A1
◦ SRY (sex-determining region)
◦ TSPY (testis-specific protein)
◦ USP9Y
◦ UTY (ubiquitously transcribed TPR gene on Y
chromosome)
◦ ZFY (zinc finger protein)

9. ‫ژن‬SRY(Sex-determining Region on the Y)‫در‬
‫کروموزوم‬ ‫اتوزومی‬ ‫شبه‬ ‫ناحیه‬ ‫از‬ ‫خارج‬Y‫اساسی‬ ‫نقش‬ ‫و‬ ‫داشته‬ ‫قرار‬
‫دارد‬ ‫مرد‬ ‫جنسیت‬ ‫تعیین‬ ‫در‬.SRY‫به‬ ‫شونده‬ ‫متصل‬ ‫پروتئین‬ ‫یک‬
DNA‫اس‬ ‫برداری‬ ‫نسخه‬ ‫فاکتور‬ ‫یک‬ ً‫ال‬‫احتما‬ ‫که‬ ‫میکند‬ ‫تولید‬‫ت‬.‫دیگر‬
‫کروموزوم‬ ‫روی‬ ‫بر‬ ‫جنسیت‬ ‫تعیین‬ ‫ژنهای‬X‫گرفته‬ ‫قرار‬ ‫اتوزومها‬ ‫و‬
‫اند‬.
‫سندروم‬swyer‫ژن‬ ‫در‬ ‫جهش‬ ‫توسط‬SRY

10. SHOX
‫ایفا‬ ‫پاها‬ ‫ساق‬ ‫و‬ ‫بازوها‬ ‫در‬ ‫ها‬ ‫استخوان‬ ‫تکامل‬ ‫و‬ ‫رشد‬ ‫در‬ ‫مهمی‬ ‫نقش‬
‫می‬‫کند‬
pseudoautosomal
USP9Y
‫پروتئاز‬ ‫کردن‬ ‫فعال‬ ‫کوئیتین‬ ‫یوبی‬ ‫سازنده‬9‫ناحیه‬ ‫در‬AZFA
‫اسپرم‬ ‫سلول‬ ‫توسعه‬

15.  large submetacentric
 1100 gene
 One of 2 X is inactive
 Most gene are unrelated to sex
 XIST (X Inactive Specific Transcripts)

17. ‫سازی‬ ‫غیرفعال‬ ‫مرکز‬X‫باند‬ ‫در‬Xq13‫دارد‬ ‫قرار‬.‫حاوی‬ ‫مرکز‬ ‫این‬
‫بنام‬ ‫ژنی‬XIST(X Inactive Specific Transcripts)‫است‬
‫ف‬ ‫غیر‬ ‫دارند‬ ‫قرار‬ ‫شده‬ ‫فعال‬ ‫غیر‬ ‫کروموزوم‬ ‫روی‬ ‫بر‬ ‫که‬ ‫ژنهایی‬ ‫تمام‬‫عال‬
‫نمیگردند‬.‫از‬ ‫بیش‬ ‫بیان‬ ‫آنالیز‬250‫به‬ ‫وابسته‬ ‫ژن‬X‫که‬ ‫میدهد‬ ‫نشان‬
‫حدود‬10‫تا‬15%‫میگریزند‬ ‫شدن‬ ‫فعال‬ ‫غیر‬ ‫از‬ ‫ژنها‬.
‫این‬‫کروموزوم‬ ‫جزئی‬ ‫آنیوپلوئیدی‬ ‫در‬ ‫امر‬X‫دارد‬ ‫مهمی‬ ‫کاربرد‬.‫ژنهای‬
Xp‫ژنهای‬ ‫از‬ ‫بیش‬Xq‫شدن‬ ‫فعال‬ ‫غیر‬ ‫از‬‫میگریزند‬

18. ‫در‬‫سال‬۱۹۴۹‫بنام‬ ‫دانشمندی‬Barr‫های‬ ‫سلول‬ ‫در‬ ‫که‬ ‫دریافت‬
‫ک‬ ‫دارد‬ ‫وجود‬ ‫کروماتینی‬ ‫کوچک‬ ‫جسم‬ ،‫ماده‬ ‫پستانداران‬ ‫سوماتیک‬‫در‬ ‫ه‬
‫شود‬ ‫نمی‬ ‫دیده‬ ‫مردان‬ ‫سوماتیکی‬ ‫های‬ ‫سلول‬.
‫بار‬ ‫جسم‬ ‫را‬ ‫کوچک‬ ‫جسم‬ ‫این‬ ‫وی‬Barr Body‫به‬ ‫امروزه‬ ‫که‬ ‫نامید‬
‫آن‬‫جنسی‬ ‫کروماتین‬‫گویند‬ ‫می‬.‫های‬ ‫کرومزوم‬ ‫از‬ ‫یکی‬ ‫واقع‬ ‫در‬X
‫بق‬ ‫و‬ ‫ماند‬ ‫می‬ ‫باقی‬ ‫فعال‬ ‫بصورت‬ ‫سوماتیکی‬ ‫های‬ ‫سلول‬ ‫در‬ ‫زنان‬‫یه‬
‫های‬ ‫کرومزوم‬X‫شوند‬ ‫می‬ ‫غیرفعال‬ ‫و‬ ‫متراکم‬.

21. ‫های‬ ‫کرومزوم‬ ‫از‬ ‫یکی‬ ‫شدن‬ ‫فعال‬ ‫غیر‬ ‫فرضیه‬ ‫اما‬X‫در‬ ‫ماده‬ ‫جنس‬
‫سال‬ ‫در‬ ،‫پستانداران‬۱۹۶۲‫خانم‬ ‫بوسیله‬Mary Lyon‫که‬ ،‫شد‬ ‫ارائه‬
‫است‬ ‫زیر‬ ‫بصورت‬:
‫الف‬:‫ه‬ ‫کرومزوم‬ ‫از‬ ‫یکی‬ ‫ماده‬ ‫پستانداران‬ ‫سوماتیکی‬ ‫های‬ ‫سلول‬ ‫در‬‫ای‬
X‫کرومزوم‬ ‫یک‬ ‫فقط‬ ‫و‬ ‫شده‬ ‫فعال‬ ‫غیر‬ ‫و‬ ‫متراکم‬X‫دارد‬ ‫وجود‬ ‫فعال‬.
‫ب‬:‫کرومزوم‬ ‫شدن‬ ‫غیرفعال‬X‫صورت‬ ‫جنینی‬ ‫رشد‬ ‫اولیه‬ ‫مراحل‬ ‫در‬
‫گیرد‬ ‫می‬.‫مرحله‬ ‫در‬ ‫یعنی‬‫لقاح‬ ‫از‬ ‫بعد‬ ‫روز‬ ‫سه‬ ‫یا‬ ‫موروال‬‫فع‬ ‫غیر‬ ،‫ال‬
‫شود‬ ‫می‬ ‫کامل‬ ‫جنینی‬ ‫اول‬ ‫هفته‬ ‫پایان‬ ‫تا‬ ‫و‬ ‫شروع‬ ‫شدن‬.
‫ج‬:‫کرومزوم‬ ‫شدن‬ ‫فعال‬ ‫غیر‬X‫کامال‬ ‫مادری‬ ‫یا‬ ‫پدری‬ ‫منشاء‬ ‫با‬
‫یک‬ ‫که‬ ‫هنگامی‬ ‫اما‬ ،‫است‬ ‫تصادفی‬X‫سلول‬ ‫یک‬ ‫در‬ ‫انتخابی‬ ‫بصورت‬
‫میتو‬ ‫طریق‬ ‫از‬ ‫و‬ ‫سلول‬ ‫این‬ ‫از‬ ‫که‬ ‫هایی‬ ‫سلول‬ ‫تمام‬ ،‫شد‬ ‫فعال‬ ‫غیر‬‫ز‬
‫همان‬ ‫و‬ ‫نموده‬ ‫تبعیت‬ ‫وضعیت‬ ‫همان‬ ‫از‬ ،‫شوند‬ ‫می‬ ‫حاصل‬X‫غیر‬ ‫را‬
‫کنند‬ ‫می‬ ‫فعال‬.

22. ‫است‬ ‫این‬ ‫شود‬ ‫می‬ ‫مطرح‬ ‫که‬ ‫سوالی‬ ‫اما‬:‫کرومزوم‬X‫شود؟‬ ‫می‬ ‫فعال‬ ‫غیر‬ ‫چگونه‬
‫از‬ ‫زیادی‬ ‫های‬ ‫کپی‬ ‫سلول‬ ‫در‬SiRNA or Small interference RNA
‫این‬ ‫که‬ ‫شود‬ ‫می‬ ‫تولید‬RNA‫کرومزوم‬ ‫شدن‬ ‫کروماتینه‬ ‫هترو‬ ‫عمل‬ ‫ها‬X‫انجام‬ ‫را‬
‫دهند‬ ‫می‬.‫این‬SiRNA‫کرومزوم‬ ‫روی‬ ‫ها‬X‫نشسته‬ ،‫شود‬ ‫فعال‬ ‫غیر‬ ‫است‬ ‫قرار‬ ‫که‬
‫کنند‬ ‫می‬ ‫فعال‬ ‫غیر‬ ‫را‬ ‫آن‬ ‫نهایت‬ ‫در‬ ‫و‬.
‫کرومزوم‬ ‫شدن‬ ‫فعال‬ ‫غیر‬ ‫اثبات‬ ‫برای‬ ‫که‬ ‫آزمایشاتی‬ ‫از‬ ‫یکی‬X‫قرار‬ ‫این‬ ‫از‬ ‫شد‬
‫بود‬:
‫کرومزوم‬ ‫روی‬X‫بنام‬ ‫دارد‬ ‫وجود‬ ‫ژنی‬H‫خونی‬ ‫کم‬ ‫ضد‬ ‫فاکتور‬ ‫سنتز‬ ‫مسئول‬ ‫که‬‫یا‬
Anti Hemophilia Factor‫باشد‬ ‫می‬.‫در‬ ‫خون‬ ‫انعقاد‬ ‫باعث‬ ‫فاکتور‬ ‫این‬
‫شود‬ ‫می‬ ‫خونریزی‬ ‫هنگام‬.
‫کروکزوم‬ ‫شدن‬ ‫کروماتینه‬ ‫هترو‬ ‫که‬ ‫کنیم‬ ‫فرض‬ ‫اگر‬X‫فاکتور‬ ‫این‬ ،‫نداشت‬ ‫وجود‬
‫باشد‬ ‫مردان‬ ‫از‬ ‫بیشتر‬ ‫زنان‬ ‫پالسمای‬ ‫در‬ ‫باید‬(‫کرومزوم‬ ‫دو‬ ‫زنان‬ ‫چون‬X‫و‬ ‫دارند‬
‫یکی‬ ‫مردان‬.)
‫کرومزوم‬ ‫دو‬ ‫از‬ ‫یکی‬ ‫زنان‬ ‫در‬ ‫که‬ ‫چرا‬ ،‫بود‬ ‫برعکس‬ ‫کامال‬ ‫مشاهده‬ ‫نتایج‬ ‫ولی‬X
‫سا‬ ‫جنس‬ ‫دو‬ ‫هر‬ ‫پالسمای‬ ‫در‬ ‫خونی‬ ‫کم‬ ‫ضد‬ ‫فاکتور‬ ‫مقدار‬ ‫و‬ ‫شود‬ ‫می‬ ‫فعال‬ ‫غیر‬‫لم‬
‫بود‬ ‫برابر‬.

23. • Female mammals have an XX genotype.
– Expression of sex-linked genes is similar to autosomal genes in females.
– X chromosome inactivation randomly “turns off” one X chromosome
– ensures that females, like males, have one functional copy of the
X chromosome in each body cell
X

24.  The Y chromosome was identified as a sex-
determining chromosome by Nettie
Stevens at Bryn Mawr College in 1905 during
a study of the mealworm Tenebrio molitor
 Hermann Henking
 the Y chromosome was the pair of the X
chromosome
 . Stevens named the chromosome "Y" simply
to follow on from Henking's "X" alphabetically
 That was depond on it shape

26. ‫كروموزوم‬ ‫تكامل‬ ‫نظریه‬ ‫براساس‬Y‫حدود‬ ً‫ال‬‫احتما‬۲۴۰‫تا‬
۳۲۰‫كرو‬ ‫فاقد‬ ‫كه‬ ‫خزندگان‬ ‫از‬ ‫پستانداران‬ ‫اشتقاق‬ ‫از‬ ‫پس‬ ،‫پیش‬ ‫سال‬ ‫میلیون‬‫موزوم‬
‫كروموزوم‬ ‫از‬ ،‫اند‬ ‫جنسى‬X‫است‬ ‫آمده‬ ‫وجود‬ ‫به‬.
‫کروموزوم‬ ‫حاضر‬ ‫درحال‬Y‫محتوی‬ ‫تنها‬200‫به‬ ‫نسبت‬ ‫ژن‬1100‫بر‬ ‫حاضر‬ ‫ژن‬
‫کروموزوم‬ ‫روی‬X‫دانش‬ ‫دانشمندان‬ ‫های‬ ‫بینی‬ ‫پیش‬ ‫ترین‬ ‫تازه‬ ‫براساس‬ ‫که‬ ‫است‬‫گاه‬
‫ر‬ ‫خواهند‬ ‫بین‬ ‫از‬ ‫زمان‬ ‫گذشت‬ ‫با‬ ‫نیز‬ ‫ژنها‬ ‫اندک‬ ‫تعداد‬ ‫این‬ ‫پنسیلوانیا‬ ‫ایالت‬‫فت‬.
‫کروموزوم‬ ‫تکامل‬ ‫محققان‬ ‫این‬Y‫کروموزوم‬ ‫با‬ ‫را‬ ‫انسان‬Y‫کیسه‬ ‫پستانداران‬
‫دار‬‫کردند‬ ‫مقایسه‬ ‫پوسها‬ ‫پالتی‬ ‫و‬ ‫کانگوروها‬ ‫مثل‬ ‫اولیه‬.
‫های‬ ‫کروموزوم‬ ‫که‬ ‫دهد‬ ‫می‬ ‫نشان‬ ‫مقایسات‬ ‫این‬X‫و‬Y‫جفت‬ ‫یک‬ ‫از‬ ‫ابتدا‬ ‫در‬
‫اند‬ ‫شده‬ ‫متفاوت‬ ‫تدریج‬ ‫به‬ ‫و‬ ‫شده‬ ‫ساخته‬ ‫جنسی‬ ‫غیر‬ ‫های‬ ‫کروموزوم‬.‫ای‬ ‫زمان‬ ‫از‬‫ن‬
‫کروموزومهای‬ ،‫تمایز‬X‫اند‬ ‫داده‬ ‫ادامه‬ ‫خود‬ ‫توسعه‬ ‫به‬ ‫عادی‬ ‫ریتم‬ ‫یک‬ ‫در‬.‫درحالی‬
‫کروموزومهای‬ ‫که‬Y‫نیست‬ ‫مشخص‬ ‫آن‬ ‫علل‬ ‫هنوز‬ ‫که‬ ‫منتظره‬ ‫غیر‬ ‫شتاب‬ ‫یک‬ ‫با‬
‫اط‬ ‫از‬ ‫بسیاری‬ ‫تدریج‬ ‫به‬ ‫زمان‬ ‫گذشت‬ ‫با‬ ‫دلیل‬ ‫همین‬ ‫به‬ ‫و‬ ‫اند‬ ‫کرده‬ ‫پیدا‬ ‫تکامل‬‫العات‬
‫اند‬ ‫داده‬ ‫دست‬ ‫از‬ ‫را‬ ‫خود‬ ‫ژنتیکی‬.

27. Sex Chromosome Evolution:
Y as Rotting X
A pair of
autosomes
X
SRY
YX
SRY
YX
SRY
Y

28.  Most mammals have only one pair of sex
chromosomes in each cell. Males have one Y
chromosome and one X chromosome, while
females have two X chromosomes. In
mammals, the Y chromosome contains a
gene, SRY, which triggers embryonic
development as a male
 Exception of SRY mammals
 the platypus(similarity) with the avian Z
chromosome

29.  The X and Y chromosomes are thought to have
evolved from a pair of identical
chromosomes termed autosomes
 Until recently, the X and Y chromosomes were
thought to have diverged around 300 million
years ago
 However, research published in 2010, and
particularly research published in 2008
documenting the sequencing of the platypus
genome,has suggested that the XY system would
not have been present more than 166 million
years ago

30.  Over time, the Y chromosome changed in
such a way as to inhibit the areas around the
sex determining genes(SRY) from
recombining at all with the X chromosome.
As a result of this process, 95% of the human
Y chromosome is unable to recombine
 The tips of the Y chromosome that could
recombine with the X chromosome are
referred to as the pseudoautosomal region.

32.  By one estimate, the human Y chromosome has
lost 1,393 of its1,438 original genes over the
course of its existence, and linear
extrapolation of this 1,393 gene loss over 300
million years gives a rate of genetic loss of 4.6
genes per million years. Continued loss of genes
at the 4.6 genes per million year rate would
result in a Y chromosome with no functional
genes that is the Y chromosome would lose
complete function within the next 10 million
years. Comparative genomic analysis, however,
reveals that many mammalian species

33.  The Y chromosome is passed exclusively
through sperm, which undergo multiple cell
divisions during gametogenesis. Each cellular
division provides further opportunity to
accumulate base pair mutations. Additionally,
sperm are stored in the highly oxidative
environment of the testis, which encourages
further mutation. These two conditions
combined put the Y chromosome at a greater
risk of mutation than the rest of the genome

34.  Without the ability to recombine during meiosis, the Y chromosome is
unable to expose individual alleles to natural selection. Deleterious
alleles are allowed to "hitchhike" with beneficial neighbors, thus
propagating maladapted alleles in to the next generation. Conversely,
advantageous alleles may be selected against if they are surrounded by
harmful alleles (background selection). Due to this inability to sort
through its gene content, the Y chromosome is particularly prone to the
accumulation of "junk" DNA. Massive accumulations of retrotransposable
elements are scattered throughout the Y.[10] The random insertion of
DNA segments often disrupts encoded gene sequences and renders
them nonfunctional. However, the Y chromosome has no way of weeding
out these "jumping genes". Without the ability to isolate alleles, selection
cannot effectively act upon them.
 A clear, quantitative indication of this inefficiency is the entropy rate of
the Y chromosome. Whereas all other chromosomes in the human
genome have entropy rates of 1.5–1.9 bits per nucleotide (compared to
the theoretical maximum of exactly 2 for no redundancy), the Y
chromosome's entropy rate is only 0.84.[18] This means the Y
chromosome has a much lower information content relative to its overall
length; it is more redundant.

35.  Even if a well adapted Y chromosome manages to
maintain genetic activity by avoiding mutation
accumulation, there is no guarantee it will be
passed down to the next generation. The
population size of the Y chromosome is
inherently limited to 1/4 that of autosomes:
diploid organisms contain two copies of
autosomal chromosomes while only half the
population contains 1 Y chromosome. Thus,
genetic drift is an exceptionally strong force
acting upon the Y chromosome