Sex Chromosomes and Sex-Linked Genes

Sex Chromosomes and Sex-Linked Genes PDF Author: Susumu Ohno
Publisher: Springer Science & Business Media
ISBN: 3642881785
Category : Science
Languages : en
Pages : 201

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Book Description
Natural selection operates among individual organisms which differ in their genetic constitution. The degree of hereditary variability within a species is greatly enhanced by cross-fertilization. Indeed, the mechanism of sexual reproduction occurred very early in evolution, for it is seen today even in bacteria. In Escherichia coli, fertilization occurs by passage of the single chromosome from the male into the female bacterium (LEDERBERG, 1959). In multicellular organisms, the separation of germ from soma, and the production of haploid gametes became mandatory. The gametes were of two types. One, extremely mobile, was designed to seek out and penetrate the other, which loaded with nutrients, received the mobile gamete and intiated the development of a new individual. The foundation for true bisexuality was thus laid. In the primitive state of bisexuality, whether an individual is to be a sperm-producing male or an egg-producing female appears to be decided rather haphazardly. In the worm, Banelia viridis, the minute males are parasites in the female. Larvae that become attached to the proboscis of an adult female become males, while unattached larvae sink to the bottom and become females (BALTZER, 1935). The more sophisticated state of bisexuality was initiated by setting aside a particular pair of chromosomes for specialization and making either the male or the female a heterogametic sex. Sex chromosomes as we know them were thus born.

Sex Chromosomes and Sex-Linked Genes

Sex Chromosomes and Sex-Linked Genes PDF Author: Susumu Ohno
Publisher: Springer Science & Business Media
ISBN: 3642881785
Category : Science
Languages : en
Pages : 201

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Book Description
Natural selection operates among individual organisms which differ in their genetic constitution. The degree of hereditary variability within a species is greatly enhanced by cross-fertilization. Indeed, the mechanism of sexual reproduction occurred very early in evolution, for it is seen today even in bacteria. In Escherichia coli, fertilization occurs by passage of the single chromosome from the male into the female bacterium (LEDERBERG, 1959). In multicellular organisms, the separation of germ from soma, and the production of haploid gametes became mandatory. The gametes were of two types. One, extremely mobile, was designed to seek out and penetrate the other, which loaded with nutrients, received the mobile gamete and intiated the development of a new individual. The foundation for true bisexuality was thus laid. In the primitive state of bisexuality, whether an individual is to be a sperm-producing male or an egg-producing female appears to be decided rather haphazardly. In the worm, Banelia viridis, the minute males are parasites in the female. Larvae that become attached to the proboscis of an adult female become males, while unattached larvae sink to the bottom and become females (BALTZER, 1935). The more sophisticated state of bisexuality was initiated by setting aside a particular pair of chromosomes for specialization and making either the male or the female a heterogametic sex. Sex chromosomes as we know them were thus born.

Exploring the Biological Contributions to Human Health

Exploring the Biological Contributions to Human Health PDF Author: Institute of Medicine
Publisher: National Academies Press
ISBN: 0309132975
Category : Medical
Languages : en
Pages : 287

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Book Description
It's obvious why only men develop prostate cancer and why only women get ovarian cancer. But it is not obvious why women are more likely to recover language ability after a stroke than men or why women are more apt to develop autoimmune diseases such as lupus. Sex differences in health throughout the lifespan have been documented. Exploring the Biological Contributions to Human Health begins to snap the pieces of the puzzle into place so that this knowledge can be used to improve health for both sexes. From behavior and cognition to metabolism and response to chemicals and infectious organisms, this book explores the health impact of sex (being male or female, according to reproductive organs and chromosomes) and gender (one's sense of self as male or female in society). Exploring the Biological Contributions to Human Health discusses basic biochemical differences in the cells of males and females and health variability between the sexes from conception throughout life. The book identifies key research needs and opportunities and addresses barriers to research. Exploring the Biological Contributions to Human Health will be important to health policy makers, basic, applied, and clinical researchers, educators, providers, and journalists-while being very accessible to interested lay readers.

The Origins of Genome Architecture

The Origins of Genome Architecture PDF Author: Michael Lynch
Publisher: Sinauer
ISBN:
Category : Medical
Languages : en
Pages : 518

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Book Description
The availability of genomic blueprints for hundreds of species has led to a transformation in biology, encouraging the proliferation of adaptive arguments for the evolution of genomic features. This text explains why the details matter and presents a framework for how the architectural diversity of eukaryotic genomes and genes came to arise.

Sex-linked Inheritance in Drosophila

Sex-linked Inheritance in Drosophila PDF Author: Thomas Hunt Morgan
Publisher:
ISBN:
Category : Drosophila
Languages : en
Pages : 98

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Book Description


Chromosomes Today

Chromosomes Today PDF Author: M. Schmid
Publisher: Springer Science & Business Media
ISBN: 9781402000911
Category : Medical
Languages : en
Pages : 300

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Book Description
Chromosomes Today volume 14 records the plenary proceedings of the 14th International Chromosome Conference, presenting an overview of the current concerns in plant, animal and human cytogenetics. This volume provides up-to-date information regarding relevant aspects on structure, function and evolution of chromosomes, meiosis, sex chromosomes, and cancer cytogenetics. It contains invited contributions from some of the world's leading experts in the field.

Principles of Biology

Principles of Biology PDF Author: Lisa Bartee
Publisher:
ISBN: 9781636350417
Category :
Languages : en
Pages :

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Book Description
The Principles of Biology sequence (BI 211, 212 and 213) introduces biology as a scientific discipline for students planning to major in biology and other science disciplines. Laboratories and classroom activities introduce techniques used to study biological processes and provide opportunities for students to develop their ability to conduct research.

Molecular Genetics of Sex Determination

Molecular Genetics of Sex Determination PDF Author: Stephen S. Wachtel
Publisher: Academic Press
ISBN:
Category : Medical
Languages : en
Pages : 544

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Book Description
The text is organized into two parts. Firstly, it reviews the basic biology of sex determination and summarizes ground-breaking work in mouse, marsupial and Drosophila systems. Secondly, it covers current human genetics, clinical studies and the syndromes of abnormal sex differentiation.

The Evolution of Sex Determination

The Evolution of Sex Determination PDF Author: Leo Beukeboom
Publisher: OUP Oxford
ISBN: 0191631396
Category : Science
Languages : en
Pages : 243

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Book Description
Sexual reproduction is a fundamental aspect of life. It is defined by the occurrence of meiosis and the fusion of two gametes of different sexes or mating types. Sex-determination mechanisms are responsible for the sexual fate and development of sexual characteristics in an organism, be it a unicellular alga, a plant, or an animal. In many cases, sex determination is genetic: males and females have different alleles or different genes that specify their sexual morphology. In animals, this is often accompanied by chromosomal differences. In other cases, sex may be determined by environmental (e.g. temperature) or social variables (e.g. the size of an organism relative to other members of its population). Surprisingly, sex-determination mechanisms are not evolutionarily conserved but are bewilderingly diverse and appear to have had rapid turnover rates during evolution. Evolutionary biologists continue to seek a solution to this conundrum. What drives the surprising dynamics of such a fundamental process that always leads to the same outcome: two sex types, male and female? The answer is complex but the ongoing genomic revolution has already greatly increased our knowledge of sex-determination systems and sex chromosomes in recent years. This novel book presents and synthesizes our current understanding, and clearly shows that sex-determination evolution will remain a dynamic field of future research. The Evolution of Sex Determination is an advanced, research level text suitable for graduate students and researchers in genetics, developmental biology, and evolution.

Genetics for Surgeons

Genetics for Surgeons PDF Author: Patrick John Morrison
Publisher: Remedica
ISBN: 1901346692
Category : Medical
Languages : en
Pages : 237

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Book Description
Morrison (human genetics, University of Ulster, UK) and Spence (biomedical science, University of Ulster, UK) offer an accessible reference on the genetic disorders that surgeons can expect to meet in general surgical practice. Written in non-technical language, with a glossary, list of abbreviations, and color and b&w photos and medical images, the book supplies an introduction to the nomenclature and technology of molecular biology, and will be a useful starting point for those who wish to extend their knowledge. Annotation :2005 Book News, Inc., Portland, OR (booknews.com).

Studies in Spermatogenesis

Studies in Spermatogenesis PDF Author: Nettie Maria Stevens
Publisher:
ISBN:
Category : Sex
Languages : en
Pages : 66

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Book Description