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发点科学知识、少儿不宜

Y chromosome
The Y chromosome is the one of the two sex-determining chromosomes in humans. The human Y chromosome is composed of about 60 million base pairs.

Most humans have one pair of sex chromosomes in each cell. Males have one Y chromosome and one X chromosome, while females have two X chromosomes. The Y chromosome also contains other genes needed for normal sperm production.
There are exceptions, however, some men have two Xs and a Y (ie "XXY", aka Klinefelter's syndrome), or one X and two Ys (ie XYY syndrome). There are other exceptions in which SRY (ie Sex-determining Region Y) is damaged (leading to an XY female), or copied to the X (leading to an XX male).
In humans, the Y chromosome spans about 58 million base pairs (the building blocks of DNA) and represents approximately 2% of the total DNA in a human cell. The human Y chromosome contains 86 genes, which code for only 23 distinct proteins. Traits that are inherited via the Y chromosome are called holandric traits.
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). These regions are relics of ancient homology between the X and Y chromosomes. The bulk of the Y chromosome which does not recombine is called the "NRY" or non-recombining region of the Y chromosome. It is the SNPs in this region which are used for tracing direct paternal ancestral lines.

送TA礼物

1楼2010-08-20 12:28回复

Haplogroup
In the study of molecular evolution, a haplogroup is a group of similar haplotypes that share a common ancestor with a single nucleotide polymorphism (SNP) mutation. Because a haplogroup consists of similar haplotypes, this is what makes it possible to predict a haplogroup from haplotypes. An SNP test confirms a haplogroup. Haplogroups are assigned letters of the alphabet, and refinements consist of additional number and letter combinations, for example R1b1. Y-chromosome and mitochondrial DNA haplogroups have different haplogroup designations. Haplogroups pertain to deep ancestral origins dating back thousands of years.
In human genetics, the haplogroups most commonly studied are Y-chromosome (Y-DNA) haplogroups and mitochondrial DNA (mtDNA) haplogroups, both of which can be used to define genetic populations. Y-DNA is passed solely along the patrilineal line, from father to son, while mtDNA is passed down the matrilineal line, from mother to offspring of both sexes. Neither recombines, and thus Y-DNA and mtDNA change only by chance mutation at each generation with no intermixture between parents' genetic material.

2楼2010-08-20 12:29

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Human Y-chromosome DNA haplogroups
In human genetics, a Human Y-chromosome DNA haplogroup is a haplogroup defined by differences in the non-recombining portions of DNA from the Y chromosome (called Y-DNA).
The Y chromosome consortium has established a system of defining Y-DNA haplogroups by letters A through to T, with further subdivisions using numbers and lower case letters.
Y-chromosomal Adam is the name given by researchers to a theoretical male who is the most recent common patrilineal (male-lineage) ancestor of all living humans. Estimations of the date of this common ancestor have varied significantly in different studies.

3楼2010-08-20 12:29

文盲路过

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4楼2010-08-20 12:29

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5楼2010-08-20 12:29

围观等待真相帝

IP属地:山西

6楼2010-08-20 12:30

7楼2010-08-20 12:30

Distribution of Haplogroup F
Besides the major clades G, H, IJ, and K, other patrilines derived from Haplogroup F-M89 can still be detected at a very low frequency among many populations of the southern fringe of Eurasia and Oceania, from Portugal in the west to Korea and the Malay Archipelago in the east. India, Korea, and the Ailao Mountains of Yunnan Province in southwestern China appear to be the only regions where such lineages, which are grouped for convenience as Haplogroup F*, comprise a significant portion of the Y-chromosome diversity of the modern populations. Haplogroup F* Y-chromosomes have been found to be particularly common among the Kucong or Yellow Lahu, a group of hunter-gatherers who live in the Ailao Mountains of Yunnan. Korean F* probably reflects a rare brother clade of haplogroups G, H, IJ, and K that may have experienced a geographically limited expansion during historical times, as such Haplogroup F* Y-chromosomes have not been found among the neighboring Japanese.

8楼2010-08-20 12:31

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9楼2010-08-20 12:31

小子，来这儿找翻译官、

10楼2010-08-20 12:32

Y染色体
Y染色体是一两个决定性别的人类染色体。人类Y染色体是由约60万个碱基对
大多数人都在每个单元1对性染色体。男性有一个Y染色体和一条X染色体，而女性有两条X染色体。 Y染色体的精子也包含了正常生产所需的其他基因。
但也有例外，但是，有些人有两个X的和一个Y（即“XXY”，又称克氏综合征），或一个X和2伊苏（即XYY综合征）。另外还有一些SRY基因（即性别决定区域Y其他例外）被损坏（导致一个XY女），或复制到X（导致一个XX男性）。
在人类中，约58万美元（DNA的组成部分）和Y染色体碱基对跨越代表在人体细胞大约2％的总DNA。人类Y染色体包含86个基因，其中只有23个不同的蛋白质编码。这是通过Y染色体的遗传特性被称为holandric特征。
人类Y染色体是无法与X染色体重组除拟常地区的小件，端粒（其中包括约5染色体的长度％）。这些地区之间的X和Y染色体的同源性古文物。在Y染色体不重组称为“NRY”或非重组的Y染色体的大部分地区。正是在这其中是父系祖先线追查直接使用区域的SNPs。
人类Y染色体DNA单倍群
在人类遗传学，一个人的Y染色体DNA单倍群是单倍群在DNA的非重组部分差额的Y染色体（称为Y型DNA）的定义。
Y染色体协会已经建立了一个通过到T的定义由字母Y型的DNA单倍群体系，进一步细分使用数字和小写字母。
Y染色体亚当是一个理论研究者给男性谁是最近的共同父系（男，系）的所有人类的祖先生活的名字。这个共同的祖先日期估计有显着不同的研究不同。

11楼2010-08-20 12:34

百度真强大

12楼2010-08-20 12:34

呵呵，不只百度哦，还有个金山在线翻译！哈哈哈！

13楼2010-08-20 12:36

嗯
还好我高中生物学的不错...

14楼2010-08-20 12:37

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这应该是生物老师讲的吧

15楼2010-08-20 12:37

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