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Incomplete linkage 21 chromosome number polyploidy 22

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Unformatted text preview: y 22 Chromosomal Inherit Polyploidy Occurs when eukaryotes have more than 2n chromosomes chromosomes Named according to number of complete sets of Named chromosomes chromosomes Major method of speciation in plants ­ Diploid egg of one species joins with diploid pollen of Diploid another species another ­ Result is new tetraploid species that is self-fertile but Result isolated from both “parent” species isolated ­ Some estimate 47% of flowering plants are polyploids Often lethal in higher animals Chromosome Number: Aneuploidy 23 Chromosomal Inherit Monosomy (2n - 1) Diploid individual has only one of a particular Diploid chromosome chromosome Caused by failure of synapsed chromosomes to Caused separate at Anaphase I (nondisjunction) separate Trisomy (2n + 1) occurs when an individual has three of a particular type of chromosome three Diploid individual has three of a particular chromosome Also caused by nondisjunction This usually produces one monosomic daughter cell This and one trisomic daughter cell in meiosis I and Down syndrome is trisomy 21 Nondisjunctio n 24 Trisomy 21 25 Chromosome Number: Abnormal Sex Chromosome Number 26 Chromosomal Inherit Result of inheriting too many or too few X or Result Y chromosomes chromosomes Caused by nondisjunction during oogenesis Caused or spermatogenesis or Turner Syndrome (XO) Female with single X chromosome Short, with broad chest and widely spaced Short, nipples nipples Can be of normal intelligence and function Can with hormone therapy with Chromosome Number: Abnormal Sex Chromosome Number 27 Chromosomal Inherit Klinefelter Syndrome (XXY) Male with underdeveloped testes and Male prostate; some breast overdevelopment prostate; Long arms and legs; large hands Near normal intelligence unless XXXY, XXXXY, Near etc. etc. No matter how many X chromosomes, No presence of Y renders individual ma...
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