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Karyotype, mitosis and meiosis
Karyotype, mitosis and meiosis

... Completion of 1st meiotic division may take over 40 years. First meiotic division results in formation of the 1st polar body. Second meiotic division completed after fertilisation in fallopian tube, resulting in mature ovum and 2nd polar body.  Oogenesis produces only one ovum.  Long resting phase ...
14-1 Human Heredity
14-1 Human Heredity

... 9. What does “polygenic” mean? ________________________________________________ 10. What environmental factor has improved the height of Americans? __________________________ 11. Our complete set of genetic information is called The _________________ ___________________ 12. Compared to peas and frui ...
Heredity Review Sheet - Heredity: the passing of ______ from one
Heredity Review Sheet - Heredity: the passing of ______ from one

... ** In order for a recessive trait to be seen, both alleles must be little, bb. - Heterozygous: (aka ____________) when two alleles are different, Bb. ...
Chapter 12 Inheritance Patterns and Human Genetics
Chapter 12 Inheritance Patterns and Human Genetics

...  Pedigree – (tool used by geneticists) = a family record ...
Mutations
Mutations

... • A section of DNA on a chromosome that directs the making of a specific protein is called a gene – Genes control the traits inherited by an organism • If a change occurs in a gene or chromosome, a trait of that organism may be changed • Any permanent change in a gene or a chromosome of a cell is ca ...
Name Date Class
Name Date Class

... 1. ________________ The body cells of humans contain 46 pairs of chromosomes. 2. ________________ A widow’s peak is a trait controlled by many genes. 3. ________________ In the case of sex-linked traits, only females can be carriers. 4. ________________ In females, a recessive allele on the X chromo ...
Chapter 31
Chapter 31

... The length of the inactive region varies from cell to cell. o As a result, inactivation of genes in this vicinity causes position effect variegation. Similar spreading effects occur at telomeres and at the silent cassettes in yeast mating type. ...
Mutations - Kaikoura High School
Mutations - Kaikoura High School

... • If they occur in somatic cells then they are non-inheritable, if in gametes then can be passed on to offspring. • Can be due to mistakes in DNA replication (spontaneous) or caused by mutagenic agents e.g. UV light, ionising radiation, Xrays, chemicals, viruses ...
Zoo/Bot 3333
Zoo/Bot 3333

... 1. In an animal bearing the heterozygous inversion ABCDEFGHI/ABGFEDCHI, in one meiocyte a crossover occurred between the D and E loci and another crossover occurred between the F and G loci. These crossovers involved the same two non-sister chromatids. What percentage of the crossover products fro ...
Basic Principles and Genetic Crosses
Basic Principles and Genetic Crosses

... separation of all other alleles.  Example:  If we look at an organism with two genes e.g. AaBb, each of the A’s can join with either of the B’s at gamete formation.  Thus we can have four gametes: AB, Ab, aB and ab. ...
Name Date ______ Pd - Social Circle City Schools
Name Date ______ Pd - Social Circle City Schools

... 14. What is polyploidy and where does it occur? Polyploidy is having one or more extra sets of all chromosomes. Occurs in earthworms, lethal in humans and in plants makes them stronger. 15. What does the principle of dominance state? ...
Heredity and Genetics Vocabulary
Heredity and Genetics Vocabulary

... eye color); variations of characters; determined by expression of proteins ...
PowerPoint to accompany
PowerPoint to accompany

... • a person with type A may have the genotype IA i or IA IA • a person with type B may have the genotype IB i or IB IB • a person with type AB must have the genotype IA IB • a person with type O blood must have the genotype ii ...
Human Inheritance
Human Inheritance

... Genetic Disorders are caused by defective genes. Defective genes arise from mutations in DNA. ...
Lecture 7 - Brandeis Life Sciences
Lecture 7 - Brandeis Life Sciences

... male parent, it is expressed in the heart and no other tissue. If it is inherited from the female parent, it is not expressed at all. This pattern of expression correlates precisely with a parentally imprinted methylation state evident in all tissues. Methylation of the transgene is acquired by its ...
fall final study guide
fall final study guide

... 15. An autosomal trait will occur with equal frequency in both males and females. a. True b. False 16. The law of independent assortment applies only to genes that are a. sex-linked. b. located on different chromosomes or are far apart on the same chromosome. c. located on the same chromosome. d. au ...
Autosomal & Chromosomal Disorders
Autosomal & Chromosomal Disorders

...  Most cases of DS are trisomy 21, however there are other types of DS (Mosaic and Translocation) .  Often DS is associated with some impairment of cognitive ability and physical growth as well as facial appearance.  The incidence of Down syndrome is estimated at 1 per 800 to 1,000 births, althoug ...
sex-linked traits
sex-linked traits

... sex chromosomes even though females have 2 X chromosomes and males have only 1  In each female cell, 1 X chromosome is inactivated and is highly condensed into a Barr body  Females heterozygous for genes on the X chromosome are genetic mosaics ...
CHAPTER OUTLINE
CHAPTER OUTLINE

... CHAPTER OUTLINE 24.1 Gene Linkage All the alleles on one chromosome form a linkage group because they tend to be inherited together and do not show independent assortment. 24.2 Sex-Linked Inheritance Out of 23 pairs of chromosomes, 22 are called autosomes and one pair is the sex chromosomes, so name ...
Chromosomes
Chromosomes

... Gregor Mendel is considered the father of modern genetics. He was an Austrian monk who worked with pea plants. Replaced Blending Theory with Particulate Theory of Inheritance. ...
Ch. 12 .1 12.2 Human Genetics Notes
Ch. 12 .1 12.2 Human Genetics Notes

... Nondisjunction in meiosis I results in all the gametes having abnormal numbers of chromosomes. Nondisjunction in meiosis II results in two normal gametes and two abnormal gametes. (Note that for simplicity only two pairs of homologous chromosomes are shown rather than all 23 pairs.) ...
Chapter 12
Chapter 12

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Ppt0000000

...  As the X chromosome is one of the sex chromosomes (the other being the Y chromosome), Xlinked inheritance is determined by the gender of the parent carrying a specific gene and can often seem complex.  This is due to the fact that, typically, females have two copies of the X-chromosome, while mal ...
File - Mr. Haan`s Science
File - Mr. Haan`s Science

... 1. 2 copies of each autosomal gene affect phenotype a. Inherit 1 set of chromosomes from each parent b. Homologous chromosomes could have same gene but different alleles c. Gene expression often related to whether the gene is on an autosome or sex chromosome ...
Chapter 15
Chapter 15

... Genomic Imprinting – one gene is silenced while the homologous chromosome is expressed - These alleles have different effects depending on if they come from sperm or egg - Caused by methylation ...
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Skewed X-inactivation

Skewed X chromosome inactivation occurs when the inactivation of one X chromosome is favored over the other, leading to an uneven number of cells with each chromosome inactivated. It is usually defined as one allele being found on the active X chromosome in over 75% of cells, and extreme skewing is when over 90% of cells have inactivated the same X chromosome. It can be caused by primary nonrandom inactivation, either by chance due to a small cell pool or directed by genes, or caused by secondary nonrandom inactivation, which occurs by selection. Most females will have some levels of skewing. It is relatively common in adult females; around 35% of women have skewed ratio over 70:30, and 7% of women have an extreme skewed ratio of over 90:10. This is of medical significance due to the potential for the expression of disease genes present on the X chromosome that are normally not expressed due to random X inactivation. X chromosome inactivation occurs in females to provide dosage compensation between the sexes. If females kept both X chromosomes active they would have twice the number of active X genes than males, who only have one copy of the X chromosome. At approximately the time of implantation (see Implantation (human embryo), one of the two X chromosomes is randomly selected for inactivation. The cell undergoes transcriptional and epigenetic changes to ensure this inactivation is permanent. All progeny from these initial cells will maintain the inactivation of the same chromosome, resulting in a mosaic pattern of cells in females.
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