Example - chromosome (XY). Occasionally, an accident...

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Example G = gray body g = black (ebony) body R = red eyes r = purple eyes Suppose that G and R are linked (on the same chromosome) in a particular individual and g and r are also linked P 1 GgRr X ggrr If there is no crossing-over, possible gametes for the first parent are GR and gr. If there is crossing-over, possible gametes are gR and Gr. the following results were obtained: How far apart are the G and R loci? Sex Chromosomes Humans have 23 pairs of chromosomes (46 total) chromosomes. Two of these are called sex chromosomes , the other 44 are called autosomes . There are two kinds of sex chromosomes, called the X chromosome and the Y chromosome. The X chromosome is larger and contains many genes. The Y chromosome is much smaller and contains very few genes. Normally, human females have two X chromosomes (XX) and males have one X and one Y
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Unformatted text preview: chromosome (XY). Occasionally, an accident happens in which a person is born with too many or too few sex chromosomes. In these cases, the person will be male if they inherit a Y chromosome and female if they do not. Examples of four different possibilities that produce males are shown below. The last three are abnormal. XY XXY XXXY XYY Examples of four different possibilities that produce females are shown below. Normal females are XX. X XX XXX XXXX The cross below shows that normal females produce eggs that have one X chromosome. Half of the sperm produced by normal males have an X chromosome and the other half have a Y chromosome. XX x XY This analysis shows that half of the offspring are expected to be male, half are expected to be female....
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Example - chromosome (XY). Occasionally, an accident...

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