毛发检验 Forensic Examination of Hair

毛发检验 Forensic Examination of Hair Nie Shengjie Forensic Medicine Dept

掌握毛发检验的意义； 了解毛发的组织结构、理化性质和生物学特征。掌握人毛与动物毛的鉴别及毛发的DNA测定。了解毛发其它遗传标记检测的方法、意义、结果评价。目的与要求

Biology of Hair Hair is an outgrowth of the skin and is produced from a structure called the hair follicle（毛囊）. Humans develop hair follicles during fetal development, and no new follicles are produced after birth. Hair is composed of the protein keratin(角蛋白). Keratin is also the primary component of finger and toe nails.

毛发结构 Hair Structure

毛尖 Hair tip 毛发结构 Hair Structure 毛干 Hair shaft 毛根 Hair root

1. The Hair Shaft毛干 毛发的结构

The Three Layers 髓质 The medulla 皮质 The Cortex Hair shaft 毛小皮 The cuticle 毛发的结构——毛干

①毛小皮（Hair cuticle） • The outer layer of the shaft. • Protective coating made of overlapping scales, produce a characteristic pattern • Scales always point toward tip of hair • Can be used for species identification 角化无核无色素扁平鳞状上皮细胞相互重叠排列

Diagram of Coronal Scales 冠状鳞片 Spinous Scales棘状鳞片蝙蝠毛水貂 Bat Hair Hair cuticle Mink Hair

Imbricate Scales 叠瓦状鳞片 Scale Pattern (Human) Hair cuticle

Hair cuticle Damaged shaft Healthy looking hair When the cuticle is smooth it reflects the light and gives a shiny appearance. The damage is caused by the hair being over processed when perming.

②毛皮质 Hair cortex Made of spindle-shaped cells aligned in a regular array, parallel to the length of the hair. Embedded with pigment granules that give hair its color. The color, shape and distribution of the granules provide points for forensic comparison. 梭形细胞平行色素颗粒

Cortical Fusi in Human Hair

Pigment Distribution in Human Hair Pigment Distribution in Red Human Hair Animal hairs have the pigment granules commonly distributed toward the medulla In humans, pigment granules are commonly distributed toward the cuticle, except in red-haired individuals . 色素分布 Pigment Distribution in Animal Hair

Ovoid Bodies in Cattle Hair Ovoid Bodies in Dog Hair 卵形体 Ovoid Bodies in Human Hair

特点 • 毛皮质由细长的梭形，纤维状角化上皮细胞组成，皮质细胞沿毛发的纵轴排列,皮质细胞内是纤维束的角化物质，束间是残余细胞成分、色素颗粒、气泡、退化核残余物质 • 皮质细胞富含角蛋白，由二硫键链接，结构牢固，有相当的弹性和强度，难溶于水和酸，能抗蛋白分解酶的作用,燃烧有焦糊味。

受损毛皮质 over possessing of colour treatments. incorrect choice of perm lotion tug wet hair too hard to comb through Knotting hair

③毛髓质 Hair medulla • Canal like structure of cells that runs through the center of the cortex • Presence of medulla varies quite a bit: even hair to hair • Human head hairs generally have no medulla or may be fragmented ones; except Mongoloid race whose medulla is usually continuous • Most animals have medulla that is continuous or interrupted • The shape of the medulla can help identify a species

Multiserial Ladder Medulla Uniserial Ladder Medulla Deer Medulla Animal Hair

Medullas (Trace, top; Discontinuous, middle; Continuous, bottom)

毛髓质 Hair medulla • 分布于毛发中轴，由退化、形状不一的上皮细胞残留物组成 • 细胞萎缩退化，排列松弛，含有角蛋白、核残余及色素颗粒 • 不同动物的毛髓质形态具有一定特征——人毛与动物毛鉴别

Medulla of Different Species

2.毛根 Hair root 毛发结构

2.毛根 Hair root • 毛球 hair bulb 是毛根起始端膨大球状部分，基底部分有正常的细胞质和细胞核，细胞分化为毛小皮、皮质和髓质 • 毛囊hair follicle 为一管状鞘，包裹毛根，内层为上皮根鞘，外层为结缔组织鞘 • 毛乳头hair papilla 毛根和毛囊末端膨大，底面内凹，含毛细血管和神经

3.毛尖 Hair tip 毛干的游离末端，逐渐变细而尖

一、毛发结构 Hair structre 毛尖 Hair tip 毛小皮 Hair cuticle 毛干 Hair shaft 毛皮质 Hair cortex 毛髓质 Hair medulla 毛球 Hair bulb 毛根 Hair root 毛囊Hair follicle 毛乳头 Hair papilla

二、毛发的生长 生长初期生长中期 Anagen Phase CatagenPhase 2-6 years 2-4 weeks Telogen phase 生长终期 2-6 months

1.毛发生长初期 Anagen Phase • Initial growth phase during which hair follicle is actively producing hair（生长旺盛） • phase may last 2-6 years, root is flame like in appearance. • When pulled this root may contain a follicular tag (rich source of DNA)

2.毛发生长中期 Catagen Phase A transition phase—hair grows at a decreasing rate for two to three weeks—elongated appearance as root bulb shrinks （萎缩）and is being pushed out of hair follicle .

3.毛发生长终期 Telogen phase Hair growth has ended—root takes on a club-like appearance—during two-six month period, the hair will be pushed out of the follicle causing the hair to shed naturally (自然脱落).

Catagen Hair Root 生长中期 Telogen Hair Root 生长终期 Anagen Hair Root 生长初期

三、毛发的形态与颜色

1.毛发形态 Hair shape • Hair shape (round or oval) and texture (curly or straight) is influenced heavily by genes. • Nutritional status and intentional alteration (heat curling, "perms") can affect the physical appearance of hair.

2.毛发颜色Hair color Hair color is mostly the result of pigments, which are chemical compounds which reflect certain wavelengths of visible light. 白色角质体黑色角质体红色角质体黄色、白色、淡褐色、黑色

四、毛发的分布The distribution of hair • Except for the lip, the palm, the footplate, the finger and the toes. • The body area from which a hair originated can be determined by the sample’s length, shape, size, color, stiffness, curliness, microscopic appearance, pigmentation, and the appearance of the medulla.

五、毛发的理化性质 • 性质稳定，不被沸水或中性盐溶液溶解； • 不溶于硝酸、硫酸和双氧水的混合溶液，但能脱色； • 抗碱能力弱，溶于强碱溶液中； • 缺乏水解蛋白酶，无自溶现象； • 角蛋白中含3%-5%的硫，燃烧时发出特殊气味； • 含氨基酸共18种：如胱氨酸、精氨酸等； • 毛发的微量元素与人体对食物的摄取种类、饮食习惯、吸收分解代谢及年龄有差异。

Forensic Analysis of hair • Whether the hair-like evidence in question is hair? • Whether the hair in question originated from an animal or a human? • Can the body areafrom which a hair originated be determined? Is it possible to determine if a hair was forcibly removed from the body? • Individualize a human hair.

Hairs & Fibers 毛发与纤维鉴别 Visual examination Microscopy examination Burning

人毛与动物毛鉴别Human hair & animal hair ? ? ?

The scale pattern of the cuticle in human hairs is routinely imbricate. Animal hairs exhibit more variable scale patterns. human Bat Hair Mink Hair Hair cuticle

human Cortex&medulla

The body area 毛发部位

The body area from which a hair originated

Long with moderate shaft diameter and diameter variation. • Medulla absent to continuous and relatively narrow when compared to the structure of hairs from other body areas • Often with cut or split tips • Can show artificial treatment, solar bleaching, or mechanical damage . Head Hairs 头发

高加索人头发 Head Hair of Caucasian Individual

尼罗格人头发 Head Hair of Negroid Individual

毛发检验 Forensic Examination of Hair